JEE 2014 का ग़ज़ब का सवाल || V.K. Bansal Sir ही सही solve कर पाये थे || Bhannat Maths | Aman Sir

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  • Опубликовано: 10 сен 2024
  • JEE 2014 का ग़ज़ब का सवाल || V.K. Bansal Sir ही सही solve कर पाये थे || Bhannat Maths | Aman Sir
    Notes : drive.google.c...
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Комментарии • 1,8 тыс.

  • @dhruvgupta9530
    @dhruvgupta9530 2 года назад +4401

    sochne wali baat hai, jin students ne us question ko khud se solve kiya hoga, vo kitna brilliant mindset rkhte honge in maths

    • @shreyassharma8277
      @shreyassharma8277 2 года назад +578

      Han bro,aise aise questions bane hi in bacchon ke liye hote hain jinhone apna bachpan bigad kar is exam ko diya hai

    • @kattaratheist6617
      @kattaratheist6617 2 года назад +532

      @@shreyassharma8277 depend karta hai kuch bacchon ke liye padhai hi unka bachpan hota hai.woh padhai ko enjoyment ki tarah lete hain na ki burden ki tarah.

    • @jeeaspirant3550
      @jeeaspirant3550 2 года назад +62

      @Secret Diary bhai us samay ho sakta hai ho aur uske baad se ab Sare teachers is type ke concepts batate ho
      Question to brilliant hai mai matlab shock me raha tha tha jab khud se solve kiya tha pehle ki aisa kaise ho gya

    • @jeeaspirant3550
      @jeeaspirant3550 2 года назад +28

      @Secret Diary bhai tum brilliant ho ham jaise average bacchon ke liye shock ki hi baat hai
      Bhai kuch to baat hogi ki bahuton se nahi bana

    • @jeeaspirant3550
      @jeeaspirant3550 2 года назад +9

      @Secret Diary I agree but bhia dhyan nahi rehta sab ko

  • @prabhatk
    @prabhatk Год назад +136

    If we put a=2, numerator will become -1. Keeping in mind that power is not exactly 2 but it's limiting value is 2. And -1 raised to the power 1.9999999 or 2.0000000001 will become imaginary number. Brilliant question!

  • @shubhamrajgaria
    @shubhamrajgaria 2 года назад +3615

    Coaching classes needs 2-3 days to solve this question while students are expected to sove in few minutes

    • @Biome_AZ
      @Biome_AZ 2 года назад +362

      Edit:

    • @ramesh-vm6kr
      @ramesh-vm6kr 2 года назад +98

      @@Hetubanna vhai ye question mene 30 second me kr liya kya baat kr rhe ho kitna easy question h

    • @indianengineer5802
      @indianengineer5802 2 года назад +57

      @@Hetubanna 😂😂kuch bhi ....this was one of the easy and doable question

    • @sneaky6969
      @sneaky6969 2 года назад +26

      Students unhi coaching walo k padhaye hue hote hain

    • @sneaky6969
      @sneaky6969 2 года назад +6

      @@Hetubanna kuch bhi

  • @iitjeemathspro
    @iitjeemathspro 2 года назад +673

    Amazing personality VK sir, the legend 🔥🔥🔥.
    His impact on education shall be felt forever!

    • @harshsahu1966
      @harshsahu1966 2 года назад +2

      @@kingdomalmighty119 why are you watching this?

  • @MohitKumar-ls6bb
    @MohitKumar-ls6bb Год назад +439

    I was his student in 2015 in Bansal classes
    He was a real legend🙏

    • @phonexlegend69420
      @phonexlegend69420 Год назад +6

      IIT nikla?

    • @suyashdixit8896
      @suyashdixit8896 Год назад +18

      ​@@phonexlegend69420 Sabka thode na bro IIT selection ho jata hai 😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂😂

    • @harshkumar0101
      @harshkumar0101 Год назад +9

      ​@@phonexlegend69420sabhi iit nikalne ke liye nhi padhte

    • @narutouzamaki53
      @narutouzamaki53 Год назад +5

      ​@@phonexlegend69420bhai iit nikal neh ke baad log yt pehle bas lecture dekhte hai

    • @navrez3100
      @navrez3100 Год назад +3

      @@phonexlegend69420 maybe wo MIT Massachusetts chl ho? Jruri thodi na h ki sb iit hi choose kre

  • @SarthakKapat
    @SarthakKapat 2 года назад +111

    2014 Rank 1.Chitang Murdia Isliye 117 out of 120 score kiya tha😅?

  • @vishishjaiswal4589
    @vishishjaiswal4589 2 года назад +712

    The most important thing in calculus is domain which most of students don't check.
    IIT had given the clue to check domain by writing non negative integar.
    Answer is by putting a=2 base becomes -ve and base is +ve on putting a=0
    do like if you agree

  • @ashishkumarsingh1659
    @ashishkumarsingh1659 2 года назад +132

    Bansal sir was king of kota at that time..he was the true inspiration for us at that time🙏❣️

    • @srii.abhigyan2938
      @srii.abhigyan2938 2 года назад +1

      Correct but . Too much superstition is not good at all, talent and inventiveness are more or less all, Depends on how much enthusiasm and persistence one is proving.

    • @alien3200
      @alien3200 6 месяцев назад

      ​@@srii.abhigyan2938yeah, talent is relative to a person

  • @anubhavchandra6222
    @anubhavchandra6222 2 года назад +457

    Teachers taking 1 day for the question paper and students were supposed to do it within 3 hours..

    • @maddy8229
      @maddy8229 2 года назад +13

      Bilkul sahi sir

    • @varadkhairnar7752
      @varadkhairnar7752 2 года назад +17

      @Prîñcêss behen apne ko bas ek sal Milta hai teachers logo ke pass toh 7 8 sal ka experience rehta hai,hum unse better nahi rehte fir aise task jo woh kar nahi skte hum ein karna padta hai

    • @siddhantrohila4889
      @siddhantrohila4889 2 года назад +36

      Such questions are supposed to be left.
      They are even made to be left.
      Otherwise Jee Adv toppers would have scored full marks till now.

    • @dontwastetimeyouarelosingr8172
      @dontwastetimeyouarelosingr8172 2 года назад +2

      All questions are not meant to be solved during exam it's just a trap

    • @jitugangwar721
      @jitugangwar721 2 года назад

      @Prîñcêss 0 kaise hoga

  • @adarshhoizal1164
    @adarshhoizal1164 2 года назад +457

    Bansal sir had contacts in all IITs. He used to directly obtain solutions from the IIT professors who had set the actual JEE question papers in that particular year. Hence it was technically not possible for the answers published on the website of his coaching institute to be wrong.

    • @bikramdehuri7624
      @bikramdehuri7624 2 года назад +72

      Ye andar ki baat hai. Kam logon ko yahi sachhai k baare me pata hota hai..

    • @informatives7035
      @informatives7035 2 года назад +16

      ghanta ..professer sre like judge ...ias upscthey are so age ,nothing about their future and famioy tension .
      anyone cant threat,bribe them .

    • @parijatsutradhar
      @parijatsutradhar 2 года назад +15

      I would have guaranteed marked 0 in the exam (especiallywhen the timer is running), and after seeing the key, i would have cried for making a silly mistake of not considering the negetive part...

    • @BHUMIHAR.BRAHAMAN
      @BHUMIHAR.BRAHAMAN 2 года назад +3

      @@parijatsutradhar where are u today do you qualify for this exam or not

    • @parijatsutradhar
      @parijatsutradhar 2 года назад

      @@BHUMIHAR.BRAHAMAN results are not yet out bro

  • @YashMRSawant
    @YashMRSawant 2 года назад +207

    One thing to always remember when dealing with limits. If the raise to factor is function of limiting variable then it's effect should be invariant whether that raise to factor is expressed as odd/even, even/odd, even/even or odd/odd. In our example, the limiting value of raise to factor is 2, so RHS should be 1/4 when left hand side is evaluated with the value of raise to factor is expressed as 199999/99999~2.

    • @Yashkarale120
      @Yashkarale120 Год назад +1

      No thats not the case u can evaluate easily power can be irrational for example u can compute 2½,2^2½ because
      Let 2^2½=t
      logt to base 2 =2½, which is defined
      U can further it by antilog concepts
      solve .....thats not the reason,,..... true reason is that when a=2,
      It is in form of (-ve)^something =t
      Logt to the base (-ve)=something
      This is not possible in this universe

    • @shilpirai6537
      @shilpirai6537 Год назад

      ​@@Yashkarale120ghvh

    • @umamishra956
      @umamishra956 Год назад +1

      Actually if -ve^ eventh root is not defined and here by putting a=2 we are getting f(x) = -ve and that's why a.=0 is answer

    • @YashMRSawant
      @YashMRSawant Год назад

      @@Yashkarale120 please read what i described carefully before commenting.

    • @animationworld4997
      @animationworld4997 10 месяцев назад

  • @arish8598
    @arish8598 2 года назад +136

    Sir you are 100 percent correct 💯
    Online graphing calculator also shows
    At a=0, lim x >>1 is 1/4
    As rhl is y=0.2491 at x=1.01

    • @shubhamtripathi5199
      @shubhamtripathi5199 2 года назад

      @@SahajOp Ye kaha likha hai ki non-positive aur non-negative dono nhi ho skta? Waha likha hai non-negative nahi ho skta bas. Non-negative matlab less than 0. To 0 to ho hi skta hai answer.

    • @SahajOp
      @SahajOp 2 года назад +1

      @@shubhamtripathi5199 ok , non negative is > equal to 0

  • @satyenjha8699
    @satyenjha8699 2 года назад +501

    This was a simple question,but students tend to do mistake in such questions as they apply limits partially. Partial limits can be used only in product form.

    • @siddhantgureja7803
      @siddhantgureja7803 2 года назад +9

      Partial limits apply Kari mtlb.??

    • @satyenjha8699
      @satyenjha8699 2 года назад +7

      @@siddhantgureja7803 means say for example you have lim x->a (f(x))^g(x) then you can't do it like
      lim x->a (f(x))^lim x->a g(x) unless it is not an indeterminate form. Here it is an indeterminate form so you can't seperately apply limit to base and exponent

    • @siddhantgureja7803
      @siddhantgureja7803 2 года назад +6

      @@satyenjha8699
      Bhai yaha pe kaunsi indeterminate form hai.??
      Power wali toh shyd bas 1 raise to the power infinity hoti hai..
      Jisme base 1 ko tend karta hai aur power infinity ko.

    • @satyenjha8699
      @satyenjha8699 2 года назад +6

      @@siddhantgureja7803 power aur base dono seperately 0/0 wala indeterminate form hai, isliye dono pe seperately limits use nahi kar sakte

    • @siddhantgureja7803
      @siddhantgureja7803 2 года назад +2

      @@satyenjha8699
      Haa 1 put karne pe 0^0 wali indeterminate form ban toh rahi hai.

  • @kunaljaju646
    @kunaljaju646 2 года назад +67

    Looking at this question the function is defined at 1 as the ans for the limit is 1/4,so this limit is going to be continuous for 1 and LHL=RHL=f(1),when you solve for LHL you get (0/1-a)^2 now if a is anything except 2 the ans for LHL will be approaching 0 and if a=0 then it will be in the form 0/0 which means it could be further simplified,also RHL gives 1/4 when a=0[RHL=(a+1/2)^2]

  • @soumyepratapsingh6090
    @soumyepratapsingh6090 2 года назад +174

    My maths teacher taught us this question normally in class and we didn't feel any difficulty didn't knew it was that important at that time!

    • @AltafHussain-zv4lh
      @AltafHussain-zv4lh 2 года назад +2

      Thoda cross check karne se correct option mil jata

    • @chemifi1686
      @chemifi1686 2 года назад +25

      Your teacher did the right thing.
      This man is just creating hype with the name of Bansal sir.

    • @unhatchedegg9013
      @unhatchedegg9013 2 года назад

      Same mera tution me bhi krwaha tha

    • @SandeepKumar-nm5wz
      @SandeepKumar-nm5wz 2 года назад

      These kind of teacher is appropriate for our society.

    • @chandankumarchand6686
      @chandankumarchand6686 2 года назад +3

      @@chemifi1686 exactly.....he is talking like it's end of the world...

  • @naveenkhare1979
    @naveenkhare1979 Год назад +7

    I have great interest in Maths as on today at the age of 63. Still watching match problems,Olympiad question and try to solve the problem first then tally. You are genius.I admir your way of presenting explanation .

  • @simransharma5352
    @simransharma5352 2 года назад +32

    Agar unka sahi tha toh aap ka bhi toh sahi hi tha
    Hats off for u sir😀😀😊

  • @Phoenix-rg5kt
    @Phoenix-rg5kt 2 года назад +51

    3:59 😂😂 I can't stop my laugh 😂legendery backbencher... BTW VK Sir is Undescribable🔥🔥

  • @YogeshKumar-sq7qe
    @YogeshKumar-sq7qe 2 года назад +60

    On solving we get a=0,2[For a=2, base of given limit approaches -1/2 (clearly base of given limit is -ve) and exponent approaches to 2. Since, base of limit cannot be -ve (kyo ki agar limit ka base -ve ho gya to limit inside ln will not be defined, to define limit inside ln, (1-a)/2 must be greater than o, from this we get, a

    • @uthrisar3874
      @uthrisar3874 2 года назад +4

      Base of limit kyu negative aa nahi sakta bro???

    • @s_iiitg
      @s_iiitg 2 года назад

      Kyu bhai base - ve kyu nhi ho sakh ta

    • @anshumanagrawal346
      @anshumanagrawal346 2 года назад

      @@uthrisar3874 Bhai tum khud hi socho (-0.501)^2.001 hota h kya real (just an example)

    • @uthrisar3874
      @uthrisar3874 2 года назад

      @@anshumanagrawal346 thanks a lot Bhai 👍👍👍

    • @anshumanagrawal346
      @anshumanagrawal346 2 года назад

      @@uthrisar3874 👍👍

  • @shaktisinghbhati9473
    @shaktisinghbhati9473 2 года назад +26

    The point here is that you can't replace (1-x)/1-√x by (1+√x) because at x=1 first expression is not defined but second one is.If you solve this question without substitution of 1+√x in place of (1-x)/(1-√x), by taking log both sides then using multiplication of functions property of limit and solving log part in the same way sir has done here and apply L'hospital rule in (1-x)/(1-√x). you will get only ans= 0

    • @dbjindian
      @dbjindian Год назад

      yes....

    • @rajendersony6301
      @rajendersony6301 Год назад

      absolutely right

    • @mitsu7june
      @mitsu7june 10 месяцев назад

      Why can't we replace?? Since it's tends to 1 not absolute 1

  • @rishavraj6027
    @rishavraj6027 2 года назад +88

    Because sir for a =2 base of above limit approaches -1/2 and exponent approach to 2 and since base cannot be negative
    Hence limit doesn't exist 🙏

    • @rhlsx
      @rhlsx 2 года назад +2

      @G.U.D. Temper Very well explained! 🙌🏻✨💥 Wish more emphasis is given on understanding the meaning of the concept rather than just solving questions! 🙌🏻 Thank you so much for such a detailed and awesome explanation! ✨

  • @dawnstudios7813
    @dawnstudios7813 2 года назад +52

    If we allow complex exponentiation, then a=2 should be the correct answer, one can even find lim (-1)^x as x tends to 2 on Wolfram alpha, and look at the series expansion near 2, it includes imaginary terms as well.

    • @anshumanagrawal346
      @anshumanagrawal346 2 года назад +2

      It's still wrong, (-1)^(irrational) is always undefined

    • @varun8762
      @varun8762 11 месяцев назад +1

      Complex exponentiation not in jee advance syllabus

  • @AkashRaj-vj6br
    @AkashRaj-vj6br 2 года назад +48

    I checked it in Arihant 40 years iit jee main and advanced books ..i bought it in 2019 (edition) and it's written a=2

    • @Seriouslyfunny1
      @Seriouslyfunny1 2 года назад +6

      If possible, use brilliant tutorial problems instead of arihant. They are much better quality.
      After that, use Arihant only to get an idea of PYQ.

  • @Himanshu02Sharma21
    @Himanshu02Sharma21 2 года назад +10

    It was an Easy Question...
    You just exaggerated it too much dk why??

    • @poplu8422
      @poplu8422 2 года назад +5

      Yeah Exactly 💯

    • @Himanshu02Sharma21
      @Himanshu02Sharma21 2 года назад +2

      @@poplu8422 yess why should a student waste around 30 min to a single question of limit which is also not very difficult???🤔

    • @ROHANKUMARSINGH-go2gy
      @ROHANKUMARSINGH-go2gy 6 месяцев назад +1

      Bhai is bande ne zindagi ke 10 saal barbaad kr diye ise abhi tk question hi samjh nhi aaya h 😂

  • @VSTMathsClasses
    @VSTMathsClasses 2 года назад +210

    VK Bansal sir was best....and will remain best in our hearts ever...😪

    • @srii.abhigyan2938
      @srii.abhigyan2938 2 года назад +2

      Correct but . Too much superstition is not good at all, talent and inventiveness are more or less all, Depends on how much enthusiasm and persistence one is proving.

  • @adhritimandal948
    @adhritimandal948 2 года назад +39

    If we put a=2,then it is approaching -1/2,which is negative....but we know that for a limit to exist in f(x)^g(x) form, f(x) must be greater than 0....so we reject a=2.....

    • @cgnytro5460
      @cgnytro5460 2 года назад +2

      Oo tai naki

    • @thegreatindia8013
      @thegreatindia8013 2 года назад +1

      Oo tai naki means that's why

    • @aneekmandal5430
      @aneekmandal5430 2 года назад +3

      @@thegreatindia8013 No,it means 'oh,is it?' I am also a bengali from w.b ....

  • @liberalacedemi200
    @liberalacedemi200 Год назад +5

    I am also agree with you sir because
    (1- a)^2 =1
    When a=0
    Sq of (1) or |1| is always 1
    But
    When a= 2
    Then sq of (-1) is 1
    &
    |-1| is (1, -1)
    Hence last answer is a=0 .......... Ans.

  • @prateeksingh432
    @prateeksingh432 2 года назад +28

    The expression after taking common and dividing become f(x)^g(x) form and we know in this form f(x) cannot be -ve. so If we put a =2 the f(x) becomes -ve .
    Hence ans will be zero.

  • @chanduudarapu7906
    @chanduudarapu7906 Год назад +8

    This Q is solved by Ashish sir in Lakshya Jee batch, and sir said most people say this Q is solved only by VK bansal sir but it's not, some students have solved it

    • @unknwn9274
      @unknwn9274 11 месяцев назад +1

      Bhaii yahi comment mai bhi karne wala tha😅...

  • @harshpatil924
    @harshpatil924 2 года назад +65

    sir aaaap bohat hi jyada struggle kr rhe ho hmare liye thank u sir for doing sooooooooo😍😍😍😍😍😍😍😍😍

  • @ramsaini3745
    @ramsaini3745 2 года назад +9

    90%= time waste
    10%= teaching
    Gajab ke teacher ho 🫡

  • @anandsnambiar3147
    @anandsnambiar3147 2 года назад +359

    we cannot put a=2, because when we substitute a=2 to the function we would get a negative value. but since f(x)^g(x) is only defined when f(x) is positive, and here since f(x) is coming as negative when a=2, we cannot give value of a as 2, so the ans is 0. Pls pin this comment sir if i am right
    :)

    • @Mk-hf6dv
      @Mk-hf6dv 2 года назад +23

      Bhai tum to jee me top karoge

    • @sanayamitall2470
      @sanayamitall2470 2 года назад +3

      Ge

    • @sinistershivank8010
      @sinistershivank8010 2 года назад +12

      But don't you think when you put a=2 base will be negative but exponent is 2 which is possible for negative bases
      Bcoz as much i can remember negative bases are not defined for a^x functions not for x^2 function
      So for negative base reason a=0 or 2 both correct

    • @prajojeet
      @prajojeet 2 года назад +2

      @National Thinking Framework (India Chapter) what is your source?

    • @prajojeet
      @prajojeet 2 года назад

      @National Thinking Framework (India Chapter) means how do you come across all such awesome content ?? From where??

  • @samadfaridi1309
    @samadfaridi1309 Год назад +7

    Ashish sir is legend

    • @acos126
      @acos126 Год назад

      Lakshay se ho na ?

  • @healer1609
    @healer1609 2 года назад +25

    Because if we a=2 in Main equation then value comes out negative or non positive so answer is 0

  • @sks-rd2ng
    @sks-rd2ng 2 года назад +22

    Who frame this question how intelligent he is

  • @vishnukrishnadas9233
    @vishnukrishnadas9233 2 года назад +35

    Sir , FOR (a) =2 the base approaches to -1by2 and hence this value must be rejected.

    • @narendramudi7984
      @narendramudi7984 2 года назад +1

      There is nothing about "Approach" as the limit is on "x" not on "a"

  • @nimishgupta5813
    @nimishgupta5813 2 года назад +229

    Sir Arihant 42 years pyq 1979-2020 me abhi bhi ans a=2 given hai 😂

    • @classyrydm33
      @classyrydm33 2 года назад +4

      Nhi bhai 0 hai

    • @mustafa6543
      @mustafa6543 2 года назад +1

      @@classyrydm33 nahi
      2 hi diya hua hai

    • @kumarsoham8734
      @kumarsoham8734 2 года назад +25

      physics wallah study material m 0 h

    • @harshpatil924
      @harshpatil924 2 года назад +2

      oooo bhai maaro kya hi copy krte he 😂😂😂😂😂😂

    • @nimishgupta5813
      @nimishgupta5813 2 года назад +1

      @@kumarsoham8734 oh, nice; but u haven't studied that module as i am 12th student 😃

  • @ajeetkumar-ky5ek
    @ajeetkumar-ky5ek 2 года назад +5

    See this is the problem of limit to exponents. We solve it by taking logarithm, by this method I am getting only one answer a=0.
    Previous method is wrong because base and exponents are inderterminant form and limit cannot be apply on both things simultaneously.

  • @priyam6496
    @priyam6496 2 года назад +9

    On putting a=2....(-1/2)^2 comes out but rhl and lhl is not defined becoz base is negative for example (-1/2)^1.99999999 is undefined nd (-1/2)^2.00000001 is also undefined therefore limit doesn exist.😇Always check domain in limit is must after getting ans.

  • @ChemicalFun
    @ChemicalFun 2 года назад +3

    He wasted 20 minutes out of 25. I wonder how degraded people become to make their videos lengthy .

  • @ajaymokta3258
    @ajaymokta3258 2 года назад +14

    For a= 2 base of above limit approaches to -1/2 and exponent approaches to 2 and since base cannot negative hence for a= 2 limit does not exist

  • @AnishKumar-kp9kt
    @AnishKumar-kp9kt Год назад +6

    Ashish sir solved this question and we also don't find it difficult

  • @thunderbolt6276
    @thunderbolt6276 2 года назад +10

    Reason: on solving we get two values of a=0 and a=2. On putting a=0 we get the base as tending to 1/2 and exponent as tending to 2, so limit=1/4.
    But on putting a=2 we get base tending to -1/2 and exponent tending to 2, now one would say (-1/2)²=1/4, so what's the problem but Emphasis has to be paid to the word exponent tending to 2 but not 2, so it wouldn't be defined.

    • @krishnamohapatra2432
      @krishnamohapatra2432 2 года назад

      Ekdum sahi hai...yeahi batt hai bhai 🙏

    • @Cm-zc2zx
      @Cm-zc2zx 2 года назад

      @@krishnamohapatra2432 yarr
      😂😂🤣
      Main smjh gyaa chodo

  • @jayatemihir5390
    @jayatemihir5390 8 месяцев назад +2

    Hi, a=2 cannot be the solution because then the inner term (sin(x-1)/(x-1) - a)/(sin (x-1)/(x-1)) will be negative in the neighbourhood of 1 and the exponent 1 + sqrt(x) will be fractional in the neighbourhood of x=1. So, due to this in the left or right neighbourhood of the limit will be an expression (-ve)^(fractional real number) which won't be a real number at all and hence the limit won't exist in real domain that case. So, a=0 will be the only case where the limit will take the form (+ve)^real which is allowed.
    I am already graduated from NIT Allahabad but I still watch your videos to solve problems in my mind.

  • @Ayush__Prajapati
    @Ayush__Prajapati 2 года назад +146

    A notice to all teachers and students-----
    ""Don't compare ur talent with him ""
    He is totally different and father of kota educational junction 🙂🙂😇

    • @praveenkaintura7278
      @praveenkaintura7278 2 года назад +4

      Absolutely

    • @nibbles5007
      @nibbles5007 2 года назад +1

      Tu pagal hai khaha kiya compare

    • @Ayush__Prajapati
      @Ayush__Prajapati 2 года назад +1

      @@nibbles5007 ye sabhi k liye hai 🤣

    • @srii.abhigyan2938
      @srii.abhigyan2938 2 года назад +1

      Correct but . Too much superstition is not good at all, talent and inventiveness are more or less all, Depends on how much enthusiasm and persistence one is proving.

  • @vedantjadhao8117
    @vedantjadhao8117 2 года назад +25

    Those golden days of IIT JEE preparation

    • @vladiyogiputinraj4132
      @vladiyogiputinraj4132 2 года назад +1

      Bhaiya aapka Hua IIT me just asking for some tips.....

    • @vladiyogiputinraj4132
      @vladiyogiputinraj4132 2 года назад

      I am preparing for jee mains and I don't know if I am well prepared for advanced but I will try though....

    • @gauravindoria9309
      @gauravindoria9309 2 года назад

      @@vladiyogiputinraj4132 Hii Buddy, I'll definitely help you if you want suggestion then connect with me !

    • @ravipratap7530
      @ravipratap7530 2 года назад

      @@gauravindoria9309 best books??

  • @VinaySingh-bb8mz
    @VinaySingh-bb8mz 2 года назад +12

    Sir ,
    We have (-a+1) as a base so if we 1)put a=2 then we get result-1
    2)put a=0 then we get result 1
    Hence, it is clear that a=0 is the largest one

  • @masroormalik7964
    @masroormalik7964 26 дней назад

    Zabardast Kahaani banayi hai aap ne. I am not a student but a retired engineer and I do love watching math videos.
    Wonderful.

  • @nitinverma.6236
    @nitinverma.6236 2 года назад +176

    Note -Always take log on both side when such type of questions asked.It will always give you correct answer.

    • @MathXCompt
      @MathXCompt 2 года назад +58

      Yes ...Nitin you are right
      24 min ki video bna di iss question pr aur baccho ko paka dala

    • @Sankalp-sd6fm
      @Sankalp-sd6fm 2 года назад +25

      @@MathXCompt ye bolte h vk bansal sir se solve nahi ho paya tha us time
      Aur ye khud 7 saal baad aaye h solve karne

    • @Rexghh
      @Rexghh 2 года назад +1

      agreed

    • @nehakushwah7158
      @nehakushwah7158 2 года назад

      @@kingdomalmighty119 chotu 2 v rkhena tab v 1/4 hi ayega

    • @kingdomalmighty119
      @kingdomalmighty119 2 года назад

      @@nehakushwah7158 kuchh bhi

  • @kshitizmangalbajracharya5152
    @kshitizmangalbajracharya5152 2 года назад +112

    I am not really aware about the exam this video refers to, but I believe it's not so big of an exam that you'd need to study complex analysis. So, that makes this question a simple calculus question - the ones dealt in early undergraduate level or intermediate level. And, the approach taught in calculus to evaluate the limit of the form f(x)^g(x) is to take its logarithm and find its limit. Then, exponentiating that limit shall give the required limit. To do so, you will need f(x) to be positive as it will appear in the operation of logarithm. This is the underlying assumption of such problems in the basic calculus course. You can check it by taking logarithm of the given function and proceeding with the evaluation of its limit. Since the function inside log needs to be positive, its limit will consquently be positive (by using monotonicity of limits). Taking a=2, the limit will no longer be positive. So, the only option left is to take a=0. That's what is happening. This is indeed a really good question. Now on, I will always discuss this question whenever I teach calculus.

    • @Gopal_kg
      @Gopal_kg 2 года назад +3

      Great, a wonderful explanation!

    • @AliRaza-cv9ug
      @AliRaza-cv9ug 2 года назад

      Me too.... Sir

    • @AliRaza-cv9ug
      @AliRaza-cv9ug 2 года назад +1

      You know mathematics brother..

    • @ritviksharma5949
      @ritviksharma5949 2 года назад +2

      Not so big of an exam? Just look it up once. It is given by 12 appearing students but the questions are of much higher level. This exam is one of the toughest exams on this planet.

    • @sarvendrashukla8051
      @sarvendrashukla8051 2 года назад +1

      Satisfactory words!

  • @crickethungama-ho5dp
    @crickethungama-ho5dp 2 года назад +8

    Sir a=0 hoga kyoki a=2 par f(x)=[{-ax+sin(x-1)+a} / {x+sin(x-1)-1}] ka value negative hai . g(x)=1+√x , f(x) ke power me hai . Yah defined hoga jab f(x) positive ho.

  • @gamernscholar
    @gamernscholar 2 года назад +4

    Right hand limit does not exist with a=2
    since sin(x-1) - 2(x-1) < 0 when x>1
    with Denominator being +ve the overall fraction is negative
    and (-ve)^fraction does not exist ,
    similarly LHL also do not exist , a = 2 is rejected.

    • @fireians2809
      @fireians2809 2 года назад

      sin(x-1) -2(x-1)

    • @gamernscholar
      @gamernscholar 2 года назад

      @@fireians2809 follow the graph of y = sin x vs y = x

  • @ajaychaudharycom.chaudhary6181
    @ajaychaudharycom.chaudhary6181 10 месяцев назад +1

    (1-a)^2=1
    1-a=+_1
    Sice1-a= positive value
    So, 1-a=1hoga
    Then a=0

  • @piyushrajyadav
    @piyushrajyadav 2 года назад +14

    a = 2 rakhane par base -ve hoga vahi a = 0 rakhane par base +ve hoga

  • @shreeomdubeydubey9803
    @shreeomdubeydubey9803 Год назад +6

    Bcz after putting a=2 andr ka sb -ve ho jayega and power 2+ ko tend krega jo not possible hai,,,, ashish agarwal sir student,,,,, 💪💪💪💪🦾

  • @tanishqthakur2728
    @tanishqthakur2728 2 года назад +41

    I think here we can say that since 1-x/1-rootx is a seperate function and we are applying limit on it and getting the ans as 2 which means the function in approaching to 2 not exactly equal to 2 .

  • @shubham_bandhavakar8826
    @shubham_bandhavakar8826 Год назад +2

    Agar even root lenge toh andar negative nhi hona chahiye aur kyuki power approaching hai toh denominator bohot bada number hoga jiske last ke digits 00000 hone chahiye which is even aur agar a 2 hogya toh under root mai negative number which is not possible for even root (power is approaching to 2)

  • @aryangautam3575
    @aryangautam3575 2 года назад +50

    Let me try to explain:
    As we put a=2 in the function we get negative base,right?
    And if we put x=0 we get positive base.
    Now the power is tending to 2 .As 2 is an even no. it doesn't mean that the no. tending to 2 is also an even no matter how much it is close to 2 .Now,only the even power of a non negative no. is also a non negative no. But a no. tending to 2 is not an even no. As it is given the whole expression=1/4 i.e. base can never be negative as power is not an even no. So,the value a=2 is discarded.
    So the only possible value of a is 0.

    • @iitianaakash5582
      @iitianaakash5582 2 года назад +6

      Apke charan kidhar ha sir😐🤣

    • @aryangautam3575
      @aryangautam3575 2 года назад +1

      @@iitianaakash5582 What happened?

    • @anish8373
      @anish8373 2 года назад

      Bro hatsoff

    • @aryangautam3575
      @aryangautam3575 2 года назад +1

      @@anish8373 Thanks bhai

    • @satyenjha8699
      @satyenjha8699 2 года назад +1

      No this is not correct logic. The thing is even if you reject 2 using this logic,you have still used wrong concept of limits and coincidentally got 0 as the answer. The only way to do this is to take log on both sides. You can't simply reduce the exponent to 2 as you can't apply limits seperately to base and exponent until and unless it's not an indeterminate form.

  • @kingofpughbgmi1702
    @kingofpughbgmi1702 Год назад +1

    But for
    a
    =
    2
    we get a negative number raised to the power of a rational number.
    and logarithm of a negative number is not define. [From (3)]
    This is not always defined.
    Hence
    a
    =
    0
    is the right answer

  • @pratikshasharma5555
    @pratikshasharma5555 2 года назад +4

    1-a^2) ^2 = 1.. so we can write ( 1-a^2) ^2 = 1^2 ... square se square cut gya... therefore 1- a^2 =1 ... == 1 se 1 cut gya so answer will be zero :) ""a =0""

  • @Sorya-gf7qw
    @Sorya-gf7qw 2 года назад +6

    I think the reason lies within domain of function . Since we got base of Power function approaching (1-a) raise to power some function and as a approaches 2 it's negative . I.e. function is undefined so answer is 0

  • @hiteshsirclassesmathematic5093
    @hiteshsirclassesmathematic5093 2 года назад +8

    It's my first comment on RUclips
    Answer is 0 because root of √ 1-a not equal to -1 ,√1-a=1 answer will be 0 , square root of any real value is not negative , baki sir aap batiyega apke explanation ka wait rahega 🙏

  • @priyanshubisht3163
    @priyanshubisht3163 Год назад +2

    Negative
    Non negative
    Positive
    All are different from each other

  • @shoryaprakash8945
    @shoryaprakash8945 2 года назад +20

    In exponent raised to irrational power is defined in terms of logarithm function. Like if power is rational like a^(p/q) by definition is root of equation x^q=a^p but for irrational power it's defined as follows a^b= e^(b.ln(a) )
    Here power is irrational so we need to work limit by converting it to log
    and since we are speaking about real function when a>1 for x aprroches1+ limit num sin(x-1)-a(x-1) is 0 hence it is out of domain

  • @purvanshsharma9705
    @purvanshsharma9705 Год назад +2

    sir meine ek method se kiya jisme direct a = 0 aaraha tha, Meine pure expression ko exp(limx-->1ln(expresion)^power) mein convert kardiya aur phir solve kiya

  • @mrperfect2997
    @mrperfect2997 2 года назад +8

    Sir answer 0 hi hoga kyuki power me 1-root(x) hai 2 lene per power irrational ho jata or irrational power ka value exact nahi aata hai that's why we reject 2 or x=0 lene per power rational hai toh answer exact value aayega

  • @pavanmishra9232
    @pavanmishra9232 Год назад +22

    Kon kon Ashish agrawal sir ki limit ki prayash 1.0 ki class attend karke ye video dekha raha😂😂😂😂

    • @pavanmishra9232
      @pavanmishra9232 Год назад +1

      @unknown-Mbps 😂😂😂chummu muche bhi iit bana do

  • @madhavgarg8405
    @madhavgarg8405 2 года назад +13

    As final ans is 1/4 , which is only possible when (k)^2 ., if 0

  • @Chandankumar96245
    @Chandankumar96245 Год назад +1

    0 is currect ans because if we put 0, in place of (a) then we get right hand side equal to left hand side.

  • @mathsdivergence67566
    @mathsdivergence67566 2 года назад +5

    Dear Sir, exponential function a^x mai base a ki value hamesha greater than zero (a>0) and does not equal to 1 hoti hai only then function is defined.
    And sir is question me at a=2 par base ki value -1/2 par tend kar rahi hai joki ek negative entity hai and at a=0 par base ki value +1/2 par tend kar rahi hai, therefore a=2 is rejected and correct answer is a=0.

  • @archanabansal688
    @archanabansal688 6 месяцев назад +1

    In my opinion , they tell non negative neither negative nor positive , this reason is applicable in my thought.

  • @Vinay-gy2gk
    @Vinay-gy2gk 2 года назад +38

    Sir a=0 because it satisfies the given condition that the equation is equal to 1/4. Am I correct sir

  • @pokhiti
    @pokhiti Год назад +1

    Aise tough questions ko easy banane ke liye hi hain hamare Aman sir

  • @vinodasati2883
    @vinodasati2883 2 года назад +55

    Actually air 1 of 2014 chitraang murdia got 117 out of 120 in maths just got this limits problem wrong. His mentor anna sir have told this on unacademy

    • @jeeadvanced6533
      @jeeadvanced6533 2 года назад +1

      😦😦😦

    • @avais4428
      @avais4428 2 года назад +6

      He is one of most brightest students of IIT

    • @kingdomalmighty119
      @kingdomalmighty119 2 года назад +1

      It's so simple. When found a=0 & a=2.
      After that put the value of 'a' one by one in this equation
      {(-a+1)/2}^2=1/4 and you will get
      L.H.S = R.H.S when you put the value of 'a'=0 , you will get L.H.S=R.H.S , I mean 1/4=1/4 .thanks a lot and all the best for next exam 👍🙏🥰
      I am a neet aspirant. Please blessings me..❤❤

    • @TusharKumar-ty8kh
      @TusharKumar-ty8kh 2 года назад

      @@kingdomalmighty119 how the fuck it is simple to find value 0 and 2

    • @kingdomalmighty119
      @kingdomalmighty119 2 года назад

      @@TusharKumar-ty8kh when you're preparing IIT exams That time, these type of questions are common.

  • @user-wq2ky7ic2d
    @user-wq2ky7ic2d Год назад +2

    Sir put the a=2 in the previous equation and get .
    Exponential ka base negative kaise hoga that's why we reject 2

  • @anshumanarya9215
    @anshumanarya9215 2 года назад +33

    I wouldn’t like to take the name but our maths teacher told us this same story of 0 and 2
    Now I can connect it to your one ❤️

  • @thelyceum6093
    @thelyceum6093 Год назад +1

    At very first place it is obvious that a=0 .
    Because if you don't put a=0 limit will not be indeterminate form (say if you put a=2 then numerator/denominator will be -2+1 /1+1 ) So to limit to be exist at first place a=0 .

  • @Manohar03
    @Manohar03 2 года назад +5

    Sir after getting a=2or0 then
    (1-a)^2=1 for a=2 (-1)^2=1
    for a=0 (1)^2=1
    In the limits of form f(x)^g(x) mey f(x) -ve nahi hona hai a=2 sey -ve aaya hai tho a=0 sayi hota hai sir

  • @thanav3930
    @thanav3930 Год назад +1

    If we take log on both sides and solve
    We get log(2/1-a)=log2
    Now only a=0 is the solution

  • @paramdhamduha
    @paramdhamduha 2 года назад +12

    If we put the value of a=2, our answer of the question will be undefined because√2is irretional number.

  • @dcttournaments5262
    @dcttournaments5262 3 месяца назад

    It's reallyyyy easy...take limit=L,log on both sides...solve and get a=0,2...now check domain of log which is a

  • @ivanmathsclasses1024
    @ivanmathsclasses1024 2 года назад +24

    sir if we put a=2 in the given sum it comes (3/2)^2 which is equal to 9/4 but not equal to 1/4.while a=0 satisfy Lim x tends 1 [sin (x-1)/(x-1) +a]/ [sin(x-1)/(x-1) +1] whole raise to the power 1+√x comes equal to 1/4 .Hence right answer is a=0.Here we are being unable to apply L- Hospital rule.Perhaps i may be wrong through this interpetation.Kindly reply

    • @Seriouslyfunny1
      @Seriouslyfunny1 2 года назад

      Sir there might be an error in the approach. After applying L-hospitals rule on the power term, we arrive at (.....)² = 1/4
      Now, the problem mentioned actually has "a" in a linear form, which means there is only one correct value for it. Therefore the right way would be to take square root on both sides, which would give us the answer.
      Squaring the equation would turn a linear equation to a quadratic one, adding another solution, which is incorrect.

    • @ivanmathsclasses1024
      @ivanmathsclasses1024 2 года назад

      @@Seriouslyfunny1 Exactly right beta.Thanks.

  • @shivamkumarshivamkumar6229
    @shivamkumarshivamkumar6229 Год назад +3

    Sahi me?? But asish sir ne kal karwaya ye question or jaida hard bhi nhi laga 🙄😅

  • @harshkumargupta8831
    @harshkumargupta8831 2 года назад +10

    Sir what I think is that a=2 pe jo base he woh negative ho jaega. Though power even he but still variable power variable me base positive hota he joki a=2 pe nahi balki a=0 pe hi hota he. Also in exponential chapter when we study a power x we study that a should be positive for a power x to be defined so I think that's why answer is a=0

    • @shubhajyotidebnath5651
      @shubhajyotidebnath5651 2 года назад

      Good explanation, In a function: y=a^x, we know a>0, & a not =1. So, here, on putting a=2, the limit becomes (-ve number)^(1+root x) which is not a defined function coz base isn't defined.
      But for a=2, it becomes (+ve number)^(1+root x) which is a defined function becoz base is +ve . So obviously a=0 because a=2 doesn't belong to domain of base of the given function

    • @harshkumargupta8831
      @harshkumargupta8831 2 года назад

      @@shubhajyotidebnath5651 thanks dude. You are a jee aspirant or what

    • @shubhajyotidebnath5651
      @shubhajyotidebnath5651 2 года назад

      @@harshkumargupta8831 I am not jee aspi... just as normal as everyone

    • @shubhajyotidebnath5651
      @shubhajyotidebnath5651 2 года назад

      @@harshkumargupta8831 BTW welcome.

    • @harshkumargupta8831
      @harshkumargupta8831 2 года назад

      @@shubhajyotidebnath5651 okay

  • @JagdishTandi-zs3jo
    @JagdishTandi-zs3jo 6 месяцев назад +2

    14:04 at the moment he knew who is king of maths.

  • @lg.gaming3673
    @lg.gaming3673 2 года назад +5

    a 2 or 0.
    but for a= 2 base of above limit approaches be negative hence limit does not exist.
    Therefore a=0

  • @rubikscube-aryanpandey671
    @rubikscube-aryanpandey671 Год назад +5

    Ashish aggarwaal sir bol rhe the aisa kuch nhi hai ki sirf bansal sir hi solve kr paye the

  • @FunnyReels119
    @FunnyReels119 2 года назад +30

    For a=2 we get a negative number raised to the power of a rational number. This is not always defined.
    Hence a=0 is the right answer.

    • @kingdomalmighty119
      @kingdomalmighty119 2 года назад

      It's so simple. When found a=0 & a=2.
      After that put the value of 'a' one by one in this equation
      {(-a+1)/2}^2=1/4 and you will get
      L.H.S = R.H.S when you put the value of 'a'=0 , you will get L.H.S=R.H.S , I mean 1/4=1/4 .thanks a lot and all the best for next exam 👍🙏🥰
      I am a neet aspirant. Please blessings me..❤❤

  • @pawanjaat7
    @pawanjaat7 2 года назад +1

    Mujhe math nhi pr kahani sunne ke lie 24 mint ka video dekha

  • @Rahul-jh8ic
    @Rahul-jh8ic 2 года назад +26

    If I put a=2 in equation I get (-1)^√x which is not defined so a=0 is correct to satisfied the equation. I hope this is correct 🙏 Mathematics lover

  • @yashvir987
    @yashvir987 Год назад +3

    Ha vo jee advance 2014 wala limits k que na Ashis aggarwal sir ne bhi kar ya hai class me lakshya jee❤aur aisi koi baat nhi hai ki sirf bansal sir hi kr par th

  • @pwop3879
    @pwop3879 2 года назад +25

    By taking log(natural log or simple log too) both side after step2 we will get the exact value of a as in Ln x ; x>0

  • @GAURAVSINGH-bd4dz
    @GAURAVSINGH-bd4dz 2 года назад +7

    Mr. K.S. SINGH, JRS Tutorials, Varanasi. I bet there is no one today like him so versatile so experienced and so savage.

  • @adithakur5260
    @adithakur5260 2 года назад +5

    sir a=2 defined nahi haii kyuki vo [f(x)]^g(x) ki form me haii aur ye tabhi defined haii agar f(x)≥0 pr a=2 dalne pr f(x) negative ho jaega

  • @MayurAvad
    @MayurAvad Год назад +6

    Ashish sir op

  • @PiyushKumar-xz6xg
    @PiyushKumar-xz6xg 2 года назад +5

    Sir ye question f(×)^g(×) ka concept use ho sakta hai for this f(×)must be greater than zero then this will be defined but a=2 it is -1/2 which is neagtive so it ia not defined so rejected .. i think

  • @sukhvirsingh1196
    @sukhvirsingh1196 2 года назад +2

    Sir ji,
    After taking the limit, we get
    (1--a)power 2/2 ki pwer =1/4
    Here only a=0 satisfied the equation only,

  • @adarsh6010
    @adarsh6010 2 года назад +4

    Sir a^x ma a>0 hona chahiye aur a=2 rakhana pr value -1/2 aata hai aur a=0 rakhane pr value 1/2 aata hai

  • @sunithaambali2299
    @sunithaambali2299 2 года назад +1

    Sir if a=2 then inner function becomes {1-x+sin(x-1)/sin(x-1)+(x-1)}^1+root x which does not satisfy condition that LHL=RHL

  • @woundedsoul1133
    @woundedsoul1133 2 года назад +4

    sir 2 we will not considered because for a =2 base of abve limit approches to -1/2 and sir exponent approches to 2 and we know that base cannot be negative hence limit doesn't exist
    hence correct is 0