How to solve trigonometry identities! (ultimate practice)

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  • Опубликовано: 20 янв 2025

Комментарии • 165

  • @sohampinemath1086
    @sohampinemath1086 Год назад +104

    Timestamps below 😊😊
    1) 0:32
    2) 4:42
    3) 7:15
    4) 9:04
    5) 10:47
    6) 13:01
    7) 15:36
    8) 19:10
    9) 24:12
    10) 29:33
    11) 32:40
    12) 36:55
    13) 42:46
    14) 45:41
    15) 49:41
    16) 57:25
    17) 1:02:07
    18 ) 1:04:49
    19) 1:07:29
    20) 1:12:09
    21) 1:16:11
    22) 1:14:50
    23) 1:20:21
    24) 1:23:58
    100 differential equations please❤❤

    • @blackpenredpen
      @blackpenredpen  Год назад +33

      Thank you!!!!!!

    • @demon-ow4vg
      @demon-ow4vg Год назад +2

      @@blackpenredpen please make a video about
      Digamma (x)=1

  • @imaginaryangle
    @imaginaryangle Год назад +68

    The amount of care you take that the viewer really gets it and doesn't trip over a step you are making is absolutely amazing

  • @ayssinaattori9313
    @ayssinaattori9313 Год назад +13

    We just started doing trig equations in school and I realised how fun it is to play around with trig identities. Really glad I found this video, it was really fun and I became more familiar with with other trig functions than sin, cos, and tan, which are the ones we've manly had thus far.

  • @blackpenredpen
    @blackpenredpen  Год назад +78

    Could someone please help me do the time stamps because it will really help all the viewers to navigate the video? I will also credit your name in the description. Thank you.

    • @shishirjha4219
      @shishirjha4219 Год назад +6

      Ok then you have to wait for an hour and a half and I don't need any credits

    • @thatomofolo452
      @thatomofolo452 Год назад +1

      Chain effect 👍👍😁

    • @L17_8
      @L17_8 Год назад +3

      Jesus loves you ❤️ please turn to him and repent before it's too late. The end times described in the Bible are already happening in the world.

    • @shishirjha4219
      @shishirjha4219 Год назад

      @@L17_8 bro is on drugs

    • @thenew3dworldfan
      @thenew3dworldfan Год назад

      I have a question. Suppose a(n) is the integer sequence A007916. Does the series (1 to inf) 1/ (A007916(n))^2 conv or div?

  • @ayssinaattori9313
    @ayssinaattori9313 Год назад +7

    42:20 still watching, doing the questions and watching your explanation if I get stuck. Thank you for all your great videos!

  • @hawtpotato90210
    @hawtpotato90210 10 месяцев назад +3

    42:40 I am with you brother. I am doing my best on the problems and you're filling in the gaps as I work on this over the course of a few days. Your videos have been valuable to my efforts to strengthen my math skills. Thank you very very very much BpRp!

    • @blackpenredpen
      @blackpenredpen  10 месяцев назад +2

      Glad to hear!! Keep up your good work and best wishes to you!

  • @abdirahmansamow7451
    @abdirahmansamow7451 Год назад +3

    you are the goat, i was struggling with this topic then you popped into my recommended list and now im decent at it, thank you

  • @ayssinaattori9313
    @ayssinaattori9313 Год назад +7

    Finished the video now, took some breaks in between. Was able to get most questions on my own but it was really fun to see how our ways of solving them differed. Especially on questions 16 and 17 I overcomplicated it a lot but I did end up at the right answer. Tank you so much!

  • @adnantasin485
    @adnantasin485 Год назад +3

    My interest in mathematics has grown so much because of you. You make so good content. Huge fan of your work. Thank you so much.

  • @JonnyMath
    @JonnyMath Год назад +5

    Hi backpenredpen!!! You always keep me motivated to record math videos!!! Sometimes I ask myself why should I continue making math videos on youtube, but then I watch one of your videos and they inspire myself to do it!!!🤗🤗🤗

  • @franciscomorales8102
    @franciscomorales8102 7 месяцев назад

    My Lord!!! Thank you very much!!! You had simplified my life!! I’m back in school after many years, and I was struggling into I found your video!!!
    Where did you got the T-shirt and the table you have on the wall???
    I appreciate your time, dedication and advice!!!

  • @ahsonkusare2352
    @ahsonkusare2352 Год назад +27

    Please next videos:24 indefinite integrals and
    24 definite integrals
    (High level problems)
    And happy teachers day

  • @professionalgster1176
    @professionalgster1176 8 месяцев назад

    Thank you so much for explaining well, I was assigned this today and was so confused and SCARED haha. Watched over 2 of your problems and I'm starting to understand!

  • @takureido3122
    @takureido3122 Год назад +6

    Intro - 00:00
    1 - 00:51 - sinx+cotxcosx
    2 - 04:40 - (secx-cosx)/sinx
    3 - 07:16 - cotx/(cscx-sinx)
    4 - 09:00 - (1+2cosx)/(2+secx)
    5 - 10:45 - 1/(1-sinx)+1/(1+sinx)
    6 - 13:00 - (2+cot²x)/csc²x-1
    7 - 15:36 - tan(x+π/4)
    8 - 19:11 - cos(3x)
    9 - 24:09 - cos(4x)
    10 - 29:32 - sec(sin^-1x)
    11 - 32:42 - cos(2tan^-1x)
    12 - 36:56 - tan(2sin^-1x)
    13 - 42:44 - csc²x+sec²x
    14 - 45:41 - cosx cos(2x)
    15 - 49:38 - sin⁴x
    16 - 57:22 - sin⁴x-cos⁴x
    17 - 1:02:04 - tanx+tany
    18 - 1:04:47 - 2tanx/(1+tan²x)
    19 - 1:07:25 - 1/(secx-1)+1/(secx+1)
    20 - 1:12:08 - (sinx+tanx)/(1+cos(-x))
    21 - 1:16:14 - cos²x-sin⁴x sec²x
    22 - 1:14:50 - (sinx+cosx)²
    23 - 1:20:18 - sinx/(1-cotx)+cosx/(1+tanx)
    24 - 1:23:57 - sec²(x/2)

  • @k3yb0ard73
    @k3yb0ard73 Год назад +1

    I love your videos, keep up the amazing content!!! Btw, I'm in Precalculus learning Trig Identities!

  • @kylewaddle7592
    @kylewaddle7592 Год назад +9

    I dont comment often but i felt that i should mention how helpful and entertaining with me learning calculus and other math. Also i loved this video

    • @blackpenredpen
      @blackpenredpen  Год назад +4

      Thank you!

    • @Dmoney_411
      @Dmoney_411 Год назад

      ​@@blackpenredpenHey I am taking AP precalculus, we are over hallways through unit 2 and it doesn't seem too bad. any suggestions on how to master my algebra (especially algebra 2) skills that are lacking from having those classes over zoom. Thank you 🙏

  • @cooldown6077
    @cooldown6077 Год назад +3

    Thank you so much. This will help a lot in my calculus studies. 🙂

  • @user-fh2rw9zh8g
    @user-fh2rw9zh8g Год назад

    Hello!! I've just finished watching 50 integrals video, and I'm so happy to see this as I'm struggling with trigonometry!

  • @frozenpeak1524
    @frozenpeak1524 Год назад

    I'm taking AP Precalculus this year and so far its not bad. So far its just been obtaining a deeper understanding of functions and what values can be obtained from the equation of a function.

  • @ITWorksSoftware
    @ITWorksSoftware Год назад

    42:40 yes, doing it with you. I've also done the 100 derivatives twice now, and the 100 algebra twice, too... Great practice!

  • @anurakumara3950
    @anurakumara3950 Год назад +1

    Thanks BpRp
    you're one of the great maths teacher 😎🖤❤

  • @NoahMartin-ii1wz
    @NoahMartin-ii1wz Год назад +130

    do 200 trig equations/inequalities in one take as fast as you can 😂😂

    • @L17_8
      @L17_8 Год назад +11

      Jesus loves you ❤️ please turn to him and repent before it's too late. The end times described in the Bible are already happening in the world.

    • @NoahMartin-ii1wz
      @NoahMartin-ii1wz Год назад

      make it logarithmic equations/inequalities LOLL@@L17_8

    • @user-fh2rw9zh8g
      @user-fh2rw9zh8g Год назад +2

      I wish he doooesss I'm currently self studying trigonometry and this would be so helpful

    • @robertcampomizzi7988
      @robertcampomizzi7988 Год назад +2

      Listen to the very last line of "Alphabet Aerobics" by Blackalicious and you'll know why I think you should.

    • @robertcampomizzi7988
      @robertcampomizzi7988 Год назад +5

      ​​@@L17_8if Jesus was a carpenter then he used trigonometry. Why didn't they write that trig down in the Bible? I'm just asking questions.

  • @RishavPlayz2007
    @RishavPlayz2007 Год назад

    42:40 yes i am following along solving all the questions, they're pretty easy, excited for the upcoming questions

  • @r.i.p.volodya
    @r.i.p.volodya Год назад

    Many THANKS for all the time you put into your videos. I find you inspirational 😁

  • @seshansahoo7913
    @seshansahoo7913 Год назад +1

    Happy Teacher's day Sir. Today 5th September every year in India we celebrate Teacher's Day to so our love toward the teachers. Your lecture are just brilliant i following your channel since 2020.thak you sir for everything.

  • @culater
    @culater 2 месяца назад +1

    WONDERFUL 👍

  • @TheZerovirus1000
    @TheZerovirus1000 Год назад +1

    42:39 I could watch a movie of these

  • @tariqallali4507
    @tariqallali4507 Год назад +2

    Thanks prof i really learned a bunch of things

  • @Subham-Kun
    @Subham-Kun Год назад +1

    49:24 "If I did my math right" - If this man makes mistakes in addition, I am allergic to numbers

  • @notboboi9977
    @notboboi9977 10 месяцев назад +1

    1:06
    if u look at the captions..
    cosx over se-

  • @JustTruth-x7g
    @JustTruth-x7g 2 месяца назад

    ياخي احبها والله , الرياضيات عشق مو طبيعي

  • @jaii5955
    @jaii5955 Год назад +2

    I definitely loved your math questions ❤😮

  • @ahmet00fx
    @ahmet00fx 11 месяцев назад

    i am a 12th grade student in Turkey and these questions are way easy than I expected.

  • @demiryumruk1423
    @demiryumruk1423 8 месяцев назад

    for q6 an alternative solution would be to take the -1 as being equal to -sin^2(x)-cos^2(x) (multiplying original identity by -1) and substituting, then simplifying the equation down to sin^2(x)
    really helpful video, i love all your tutorials

  • @signalsensei
    @signalsensei Год назад +2

    Thanks professor ! Please also make video on analytical geometry

  • @scottleung9587
    @scottleung9587 8 месяцев назад

    Awesome job!

  • @mikeheyburn9716
    @mikeheyburn9716 Год назад

    This is terrific Steve

  • @sajuvasu
    @sajuvasu Год назад +2

    Love you sir....❤️❤️❤️
    From india
    We aren't studying Trigonometry..
    But i understood all you taught....
    On the 14th question i think we can simplify it to
    Cos(x)Cos(2x)=2Cos³(x)-Cos(x)
    Its heartbreaking to see the expression being not factorised... 🤣🤣
    Any way..
    Big fan sir
    You are wonderful...🔥🔥❤️❤️
    (And Happy teacher's day also❤️)

  • @a.guzman1512
    @a.guzman1512 9 месяцев назад +1

    What is that reference board you are using and where can I get it? Great video!

  • @henridelagardere264
    @henridelagardere264 Год назад +2

    24 Trig Problems done in *one* take, that's gotta be BPRP, aka 'The Beast'. Identity mathematics presented the way we spoilt brats have grown used to. Don't take this man for granted, though!

    • @L17_8
      @L17_8 Год назад +1

      Jesus loves you ❤️ please turn to him and repent before it's too late. The end times described in the Bible are already happening in the world.

  • @danielputrahandana2982
    @danielputrahandana2982 Год назад +6

    I watch these while eating because I dont know what Video to watch

  • @rubensf7780
    @rubensf7780 10 месяцев назад

    1:03:31 Easy, cancel cos from both sides

  • @marshallmanz123
    @marshallmanz123 Год назад

    You deserve more views man.

  • @dannyfarias6607
    @dannyfarias6607 Год назад +1

    Thank you so much for this amazing video

  • @Jeepreparation-z9n
    @Jeepreparation-z9n Год назад

    Hey man you are really an inspiration for me.your passion keeps me motivated ❤

  • @kirbo722
    @kirbo722 Год назад

    This video was VERY helpful, thank you!!

  • @ManasvinShrimali
    @ManasvinShrimali Год назад

    at 14:37 sir you can also write 2sin^2(x) as sin^2(x) + sin^2(x) + cos^2(x) - 1=sin^2(x)

  • @stevefurrier9932
    @stevefurrier9932 7 дней назад

    2:59 There is a sinx ina denominator,so don't we need to write down,that sinx can't be zero?

  • @samarjitdasIISERkol
    @samarjitdasIISERkol Год назад +2

    Happy Teacher's Day Love from India ❤ 🇮🇳

  • @foolwhodreams
    @foolwhodreams Год назад

    thank u for this. i took ap calculus bc and skipped calc 1 and 2, and im scared of trig identities coming up in chapter 12 for calculus 3 !! big fan

  • @ArthurvanH0udt
    @ArthurvanH0udt 10 месяцев назад

    I would love it if you’d do some extra identities for the parabolic version of trig fies. So cosp and sinp identities! Why? Cause they behave somewhat different than the normal sin/cos and hyperbolic sinh/cosh versions!

  • @crazyteamoffici7556
    @crazyteamoffici7556 Год назад +1

    Love you sir ❤❤❤❤

  • @carterbagvitch5964
    @carterbagvitch5964 Год назад +1

    I ran into an interesting trig problem on my no calculator pre-calc/alg 2 test and was wondering how to do it since I only had solutions and all my teachers said there had to be a trick they didn’t know. The problem was
    If sin(x)+cos(x)=1/3, what does ((sin(x))^5)+((cos(x))^5)=

    • @adamhurt6140
      @adamhurt6140 Год назад

      what was the answer they gave you?

    • @carterbagvitch5964
      @carterbagvitch5964 Год назад +1

      @@adamhurt6140 I figured it out. The answer was 344, but thats cause they asked for the answer in fractional form (k/w), and then the answer is k+w. thats obviously not a critical step, so I didnt include it. If you want to know, u take pascals triangle and expand it out with sin(x) and cos(x), isolate sin^5(x) +cos^5(x), then factor and break down the rest of it using trig identities and the given. Also have to realize that since sin(x)+cos(x)=1/3, cos(x)*sin(x)=-4/9. thats also key

  • @datarioplays
    @datarioplays Год назад

    Do more integral battles between elementary and non-elementary ones! The one you did 4 years ago wasn’t enough for me.

  • @احمدعجينة-د2ل
    @احمدعجينة-د2ل Год назад +1

    Master of it ❤

  • @ChiefToad619
    @ChiefToad619 Год назад

    I lose sleep over these videos, even though I may or may not know the content😅

  • @yugam6578
    @yugam6578 Год назад +1

    Could you please make a video on jee advanced maths section

  • @vivekgupT______________
    @vivekgupT______________ Год назад +2

    Bro you are awesome I love you ❤❤ I am from india and I am like maths

  • @lolprogamer7662
    @lolprogamer7662 2 месяца назад

    I don't understand Q9 from 25:47

  • @talentlogic1512
    @talentlogic1512 Год назад +1

    I like this a lot. Thank you my friend.

  • @humester
    @humester 4 месяца назад

    Q13: I had 1/[(sin^2(x))(cos^2(x))]=4/[2(sin(x))(cos(x))]^2=4/[sin(2x)]^2= 4csc^2(2x). Would this be considered a correct answer?

  • @divinitas604
    @divinitas604 Год назад

    Where do I find the identities board?

  • @walter9029
    @walter9029 Год назад

    Is ex. 2 an identity? Because in the original fraction all values equal to kxpi are not in the domain.

  • @suryatejacv3042
    @suryatejacv3042 10 месяцев назад

    Hai sir can you discuss telescopic sums with alternating positive negative sums

  • @thenew3dworldfan
    @thenew3dworldfan Год назад

    I have a question. Suppose a(n) is the integer sequence A007916. Does the series (1 to inf) 1/ (A007916(n))^2 conv or div?

  • @illumexhisoka6181
    @illumexhisoka6181 Год назад

    7 can be simplified to tan(2x)+sec(2x)
    and 13 can be 4sec^2(2x)

  • @TanmaY_TalK
    @TanmaY_TalK Год назад

    Do a 100 question One Shot version and put in 100 question playlist

  • @dinoortolani6794
    @dinoortolani6794 Год назад

    you're amazing thanks

  • @yoshikagekiraaaaa
    @yoshikagekiraaaaa Год назад +2

    nice!

  • @sceditzofficial42069
    @sceditzofficial42069 Месяц назад

    They just started Trigonometry in my tution and lets just admit that it is too fun at this point...

  • @themultiroundergamer6073
    @themultiroundergamer6073 Год назад

    hey whats that black identity board you have hanging beside the whiteboard? is it available online?

  • @humester
    @humester 4 месяца назад

    Q14: cosx*cos2x=cosx*(2cos^2(x)-1)=2cos^3(x)-cos(x) Is this OK?
    Setting 2cos^3(x)-cos(x)=1/2(cos(x)+cos(3x) ==> cos(3x)=4cos^3(x)-3cos(x)

  • @flazeanimations
    @flazeanimations Год назад +1

    Idk why I always feel satisfied when he erased the whiteboard 😂

  • @ChristianRosenhagen
    @ChristianRosenhagen Год назад

    13 is stunning

  • @FVerz
    @FVerz Год назад

    26:34 Bro acts like he just made the height of 2 tall buildings approach 0m in 2001

  • @lgooch
    @lgooch Год назад

    Do inverse trig identities next!

  • @antonioaccogli1014
    @antonioaccogli1014 Год назад

    I am doing to do your test to repeat for my school test... i will tell you how it will go

  • @jitenderbajaj1808
    @jitenderbajaj1808 Год назад

    Plz solve Integral of log base 2(x*(sin2ex))

  • @Subham-Kun
    @Subham-Kun Год назад

    26:20 It is unbelievable that even the GOAT of Mathematics, who alone is strong enough to beat Lord Wolfram|Alpha, is lagging!!!!!!!!!!! THIS IS ALARMING FOR THE DIMENSION OF MATHEMATICS!!!!!!!!!!!!

  • @roof310
    @roof310 Год назад

    can you do inequalities please

  • @stavzee
    @stavzee Год назад

    His smile just makes me wanna study more

  • @aali-fg8mg
    @aali-fg8mg Год назад

    I love you man

  • @FelpSbtw
    @FelpSbtw Месяц назад

    nice video

  • @zoro8800
    @zoro8800 11 месяцев назад

    these were very easy as I am in high school

  • @brucefrizzell4221
    @brucefrizzell4221 8 месяцев назад +1

    I pick up a lot of small details in these longer videos!

  • @_maxmath
    @_maxmath Год назад

    Hi bprp can u please do a video to show us how to calculate cos(x+y+z)?

    • @Apollorion
      @Apollorion Год назад

      First you add x, y and z together, then you calculate the cosine of that sum.
      Or is that not what you mean?
      edit: e.g. do you want a formula that distributes the x, y and z into their 'own' trigonometric functions? If so then just apply the sum formula's for the cosine and sine i.e.
      sin(a+b)=sin(a)cos(b)+sin(b)cos(a)
      cos(a+b)=cos(a)cos(b)-sin(a)sin(b)
      and of course, begin with splitting one of the x,y and z terms off from the other two, and after that split the sine and cosine that other pair (and that's why I also mentioned the sum formula for the sine).

  • @sapoman01
    @sapoman01 5 месяцев назад

    my comment down below at the 42:39 time stamp ⏯

  • @prajjwalnarayan8001
    @prajjwalnarayan8001 Год назад

    Amazing

  • @Tomuchfanforfon
    @Tomuchfanforfon Год назад

    Good teacher watching from india guys reply where are you watching from?

    • @carultch
      @carultch Год назад

      I like your Nepal flag.

  • @amarendranathhazra4142
    @amarendranathhazra4142 Год назад

    Do all the 24 identities you did but hyperbolic trig instead

  • @humester
    @humester 4 месяца назад

    Q17: [tan(x)+tan(y)]/[1-tan(x)tan(y)]=tan(x+y). So, tan(x)+tan(y)=tan(x+y)[1-tan(x)tan(y)] Is it necessary to reduce to sines and cosines?
    {sin(x+y)[1-(sinx/cosy)*(siny/cosy)]}/cos(x+y)=sin(x+y)[cos(x)cos(y)-sin(x)sin(y)]/[cos(x+y)cos(x)cos(y)]=sin(x+y)cos(x+y)/[cos(x+y)cos(x)cos(y)]=sin(x+y)/cos(x)cos(y)

  • @sohampinemath1086
    @sohampinemath1086 Год назад +2

    Please do 100 differential equations I need them for my exams😭😭

    • @amitlanis3104
      @amitlanis3104 Год назад

      yesss that would be super helpful😁

    • @L17_8
      @L17_8 Год назад +1

      Jesus loves you ❤️ please turn to him and repent before it's too late. The end times described in the Bible are already happening in the world.

    • @parv840
      @parv840 Год назад

      12 th m h kya bhai

  • @salvadorsabateromero2258
    @salvadorsabateromero2258 Год назад

    18:55

  • @davidthomas6043
    @davidthomas6043 Год назад +1

    I don't understand why he puts cos3x = (cosx)(cos2x)..This seems wrong, because for example, cos 60 = o.5, but cos 20 is .9397 and cos 40 is .766, and multiplying these these gives an answer of of .7198. which is nowhere near .5 ! Can someone please explain? I Thanks

    • @AttyPatty3
      @AttyPatty3 Год назад

      Hey David! He didn't put cos 3x = (cosx) (cos2x) instead what he did was simply write the 3x as 2x + x. cos(3x) = cos(2x + x)

    • @davidthomas6043
      @davidthomas6043 Год назад

      Thanks for answering. I now see that what he wrote was (cos x)(cos2x- minus (sin x)(sin 2x). Silly me !! @@AttyPatty3

    • @davidthomas6043
      @davidthomas6043 Год назад

      Further to mt previous reply, can you please tell me if there is any way available to derive the formula cos (A + B) = cos A.cos B - sin A.sin B ?@@AttyPatty3

  • @DazHuang72
    @DazHuang72 Год назад

    Calc 2 savior

  • @PIKI146
    @PIKI146 Год назад

    I now prefer to stay home and do calculus on my weekends

  • @gamerpedia1535
    @gamerpedia1535 Год назад +1

    Cool thing to note:
    8cos⁴(x) - 8cos²(x) + 1 = 8sin⁴(x) - 8sin²(x) + 1

  • @lordpz3518
    @lordpz3518 8 месяцев назад

    plz teach mathematicalinduction

  • @SmSitutul
    @SmSitutul Год назад

    broo ❤❤

  • @Sanatan_saarthi_1729
    @Sanatan_saarthi_1729 Год назад

    Challenge:- solve 100 ordinary differential equations in one go,,,,next 100 partial differential equations in one go