Discriminant of quadratic equations | Polynomial and rational functions | Algebra II | Khan Academy

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  • Опубликовано: 28 дек 2024

Комментарии • 183

  • @CrazyNateKosty98
    @CrazyNateKosty98 10 лет назад +346

    I gotta give it to you, I learned more from you than my teacher

  • @skuffd-semicolon
    @skuffd-semicolon 5 лет назад +191

    The amount of OOOOHHHH!!!! moments I had after watching this.......

    • @sayloraks9334
      @sayloraks9334 3 года назад +2

      Wow. Thanks for making me feel bad. I had none😪

    • @FishNugget-we9oi
      @FishNugget-we9oi 6 месяцев назад

      @@sayloraks9334other people learn differently it good to let those who dont know to learn

  • @crazyloco97
    @crazyloco97 11 лет назад +82

    I learned in 2 minutes of this video what took me 1 hour in class to get confused over

  • @aucool7869
    @aucool7869 7 лет назад +7

    khan academy just makes my life easier. My teacher makes everything all complicated but Sal just makes it simple and easy to understand. THANK YOU KHAN ACADEMY

  • @tazreenkhan4890
    @tazreenkhan4890 3 года назад +3

    Deciding to watch this video is one of the best decisions I ever took in my life.

  • @codingwithkenny6492
    @codingwithkenny6492 4 года назад +3

    Sal is the best math teacher in my opinion. He simplifies the mathematical computation and makes it much less confusing than most Math teachers.

  • @musiciseverything333
    @musiciseverything333 12 лет назад +9

    Thank you dude! I fell asleep in class. Watching your videos are going to help me get through Algebra 1.

  • @Flameplaysofficial
    @Flameplaysofficial 7 лет назад +29

    I learned more from you than my Teachers way less confusing

  • @ashaa.5616
    @ashaa.5616 9 лет назад +47

    oh my god, thank you so much for this because math has not been life.

    • @colemanroberts6827
      @colemanroberts6827 9 лет назад

      +Asha A. crystal castles!

    • @randomfandom33
      @randomfandom33 7 лет назад

      mmmmmm... saying "oh my god" is technically blasphemy

    • @glnpy
      @glnpy 5 лет назад +5

      @@randomfandom33 be quiet

  • @just_magneee3185
    @just_magneee3185 4 года назад +1

    Teacher in this academy is better than my teacher.

  • @benwalker3771
    @benwalker3771 9 лет назад +10

    i dont think i would pass tests without you. cheers mate

  • @liquidsmoothgrr
    @liquidsmoothgrr 5 лет назад +6

    Watching this because my teacher got mad and she didn't teach this lesson to us but we're having a quiz about this tomorrow. Thanks a lot.

  • @futurine8197
    @futurine8197 6 лет назад +17

    Every time I finish a video is like "this is so easy how did i not understand it before"

  • @iamthejustin7420
    @iamthejustin7420 9 лет назад +16

    omg what would happen if khan academy dies, then i would fail every maths test LOVE YOU KHAN ACADEMY KEEP IT UP

  • @todayjanuary2012
    @todayjanuary2012 12 лет назад +48

    My teacher: ***stacks piles of papers on my desk*** DO IT!
    You: OK... Let's go over this slowly
    YOUR THE BEST!! I ACTUALLY UNDERSTAND WHAT I'M DOING IN MATH CLASS NOW!!! :D

  • @valeriecrespo4637
    @valeriecrespo4637 5 лет назад +12

    What if you have to solve for no real solutions with [i]

    • @mikeadriano4391
      @mikeadriano4391 5 лет назад +4

      you can still solve them using the formula. if b^2-4ac is negative [(-b^2+4ac)^(1/2)].i equals to (b^2-4ac)^(1/2)

  • @diguiane
    @diguiane 4 года назад +2

    Now im done with my modules

  • @loversjustkeeploven
    @loversjustkeeploven 13 лет назад +12

    Aced my final. thanks breh! u saved me from military school.

  • @stasha8611
    @stasha8611 4 года назад +2

    That really helped

  • @aletheaplass6557
    @aletheaplass6557 4 года назад +2

    Your handwriting is superb

  • @dimeg52
    @dimeg52 3 года назад

    I’m taking algebra 2 this year and the original algebra 2 teacher went to another school and now I’m stuck with a teacher who’s said he has never taught this before. So, this really saving my career.

  • @metallizard88
    @metallizard88 4 года назад +1

    I actually started jumping of joy because I finally understood it

  • @uttkarshjha8265
    @uttkarshjha8265 3 года назад +1

    My god 11 years ago
    Cant belive

  • @thepostmandelivers.5124
    @thepostmandelivers.5124 8 лет назад +2

    Great video straight to the point and clear, great job

  • @Ice_Screamer
    @Ice_Screamer 11 месяцев назад +1

    helpful af

  • @ForEvaW15h1nG
    @ForEvaW15h1nG 13 лет назад +1

    Well... the consistancy in your video's is through the roof. i've just started A levels after getting a good grade in Math in Gcse ... there is quite some confusion among the topics i'm studying in this new curriculum... some of the topics i've had trouble in I've searched for help, YOU have covered them all. Thank you.

  • @TheWhatnow9999
    @TheWhatnow9999 11 лет назад +6

    You save my math life thank you so much

    • @bryannguyen658
      @bryannguyen658 10 лет назад

      Agree

    • @GEGE77R6
      @GEGE77R6 9 лет назад

      +Bryan Nguyen +Ryan Houston he may have saved your math lives but your grammar lives needs work.

    • @AliceDiableaux
      @AliceDiableaux 9 лет назад +6

      +GEGE77R6 How can you possibly deduct anything about someone's mastery of English grammar when he only commented one word?? Jackass

  • @sen-te8oq
    @sen-te8oq 5 лет назад +5

    i can safely say this explained and taught me more than my school.

  • @noblessus
    @noblessus 14 лет назад

    I really like your videos Sal, they are very useful for me. Quick comment:
    Instead of saying discriminant=zero means one solution, I know it would have saved me many hours of research if someone told me that we still have two solutions (like always with quadratics) but in this case the solution repeats two times. Eg: x^2-4*x+4, even though it's discriminant is zero, it still has two solutions, which are x=2 and x=2.
    Again great videos and I hope you do more calculus and physics videos!

  • @monicaairamonserate7471
    @monicaairamonserate7471 5 лет назад +3

    omyghad, thankyouuu!!! ❤️

  • @YamenNazer
    @YamenNazer 5 лет назад +1

    This is very good i loved it..but i have a question..how did we explore the formula of discriminant ?

  • @clairenime
    @clairenime 2 года назад

    5:42 wouldn’t you move the a to the other end with everything else? My teacher says x^2 has to be positive

  • @awol9914
    @awol9914 9 лет назад +2

    Very helpful. Thanks!

  • @labeebahmad6287
    @labeebahmad6287 4 года назад

    Khan academy should be the most subscribed channel on RUclips change my mind

  • @drewneugilos8681
    @drewneugilos8681 6 лет назад +4

    Is B always negative?

    • @xXxKimballxXx
      @xXxKimballxXx 6 лет назад +1

      ItsYour Gamer yes, it’s part of the equation.

    • @SirNanothy
      @SirNanothy 4 года назад

      if the value for B is already negative, then when you plug it into the quadratic formula it would then be positive.

  • @foxenbox
    @foxenbox 4 года назад +1

    I miss 2010

  • @pitrochied
    @pitrochied 3 года назад +1

    watching after 11 years also.....

  • @xiaoxiao5088
    @xiaoxiao5088 2 года назад

    Can we use the discriminant formula when the equation in linear?

  • @shizu019
    @shizu019 4 года назад

    You save me from my sufferring thank you

  • @Aashii777
    @Aashii777 3 года назад

    Thank you! ❤️

  • @shhzaid
    @shhzaid 2 года назад

    Thank u khan acedmy

  • @crazer96
    @crazer96 12 лет назад

    It touches the x-axis in two places, so the parabola goes down touches one point on the x-axis and then when it comes up again it touches a different point on the x axis.

  • @twominutepenalty
    @twominutepenalty 13 лет назад

    @Rowan9789 if 5x^2-6x=0 the constant is zero. you could feasibly write the same equation as 5x^2-6x+0=0. either way, the y-intercept would be 0, as would the x-intercept.

  • @anaisperez2704
    @anaisperez2704 4 года назад

    i wish i had you as my teacher instead sal

  • @Karin6509
    @Karin6509 7 лет назад +1

    So I put the "i" at the end of the solution in Aleks when the answer is negative?

  • @elbay2
    @elbay2 14 лет назад

    Well done! What S/W and H/W set-up do you use as a "black board"? It's very easy on the eyes!

  • @rushikeshsurywanshi2286
    @rushikeshsurywanshi2286 4 года назад

    Iam watching it now and thanks

  • @iiiijoseuy
    @iiiijoseuy 8 лет назад +6

    what real life application does using the discriminant have?

    • @HPatel-vf7ih
      @HPatel-vf7ih 8 лет назад +1

      You can use it for engineering (and stuff like that). Also, if you want to go to law school or med school you have to know it.

    • @HPatel-vf7ih
      @HPatel-vf7ih 8 лет назад

      SpiritWolf2K Hahahahha, yeah.

    • @kamilo1175
      @kamilo1175 7 лет назад

      oJose developing your brain

    • @shreyanshpandey4022
      @shreyanshpandey4022 6 лет назад

      Employment 😂😂😂😂

  • @abdias99
    @abdias99 4 года назад

    I learned more in 10 mins than in 2 hours from my class thx 🙏🏽

  • @rascaldevilz
    @rascaldevilz 12 лет назад +2

    how does two solution look like in graph ??

    • @nathanaellandicho
      @nathanaellandicho 8 лет назад +1

      it's gonna form a parabola. the two solutions are the two points where the parabola will hit the x-axis.

  • @GndmMkv
    @GndmMkv 14 лет назад

    man it helped so much that i feel like not going to school anymore

  • @obendesmond
    @obendesmond 4 года назад

    Hello sir, please which software are you using to teach? its pretty cool

  • @ayyoitzToko
    @ayyoitzToko 12 лет назад +1

    aiight bro. cya

  • @jamieg6173
    @jamieg6173 8 лет назад +1

    SO HELPFUL! Thank you!

  • @Dusevic
    @Dusevic 14 лет назад

    wooooohooo imaginary numbers!!!! u should add imaginary numbers to your linear algebra playlist. 'cause it would help me with my college course! especially rref'ing a system composed of imaginary numbers

  • @randhawaheed2720
    @randhawaheed2720 5 лет назад +2

    THANK YOU THIS IS SO GOOD
    but I've a question how does it matter if it is a rational solution or an irrational solution

    • @KayMarie-es3cr
      @KayMarie-es3cr 5 лет назад

      Nobody Iknow Yes.

    • @randhawaheed2720
      @randhawaheed2720 5 лет назад

      @@KayMarie-es3cr what does yes mean

    • @KayMarie-es3cr
      @KayMarie-es3cr 5 лет назад

      Nobody Iknow Sorry. I thought you asked if it matters if it’s rational or not

    • @randhawaheed2720
      @randhawaheed2720 5 лет назад

      @@KayMarie-es3cr it is completely fine but do you know how it matters if so

    • @KayMarie-es3cr
      @KayMarie-es3cr 5 лет назад

      Nobody Iknow do you mean why it matters?

  • @marlyjoysereno1264
    @marlyjoysereno1264 8 лет назад +2

    wait,wait
    so where do you get on 5:24
    (the orange color)
    there is discriminant
    so where did you get the 9-4? ( Discriminant 9-4(1)(6) )

    • @sun0tea
      @sun0tea 7 лет назад

      b is 3 so b squared is 9.
      You subtract 4ac from b.
      4*a (which is1)*c(which is 6)
      So, b-4ac is 9-4*1*6

    • @omardotbio
      @omardotbio 6 лет назад

      a must be equal to -1 not 1

  • @jacobrodriguez9980
    @jacobrodriguez9980 10 лет назад

    How will I know if it is rational or irrational ?? And how will I know if it is complex ??

  • @sebru
    @sebru 3 года назад

    is there a nature of roots video? i cant find one and this is the lesson in my school

  • @girlicious102
    @girlicious102 14 лет назад

    thankss this video helped alot

  • @ahmedsarker3555
    @ahmedsarker3555 4 года назад

    sir khan one question, for the first discriminant which is bsquare - 4ac > 0 you said there will be two solutions positive and negatice but in this case, the negative is less than zero so how come there can be two solutions. In this case can we say both the values which are executed are positive instead of one postive and one negative since it would consider that one of them is greater than zero but not the other one

  • @paulceltics
    @paulceltics 13 лет назад

    @loversjustkeeploven really? thats pretty awesome

  • @yellowblob3573
    @yellowblob3573 7 лет назад

    THANK YOU SOOOOO MUCH (:

  • @noobkosh
    @noobkosh 12 лет назад

    why I cant find this video in the website??

  • @user-uwo
    @user-uwo 6 лет назад +1

    thank you for the arabic translation

  • @hongrand
    @hongrand 9 лет назад +1

    Thank you!

  • @theophonchana5025
    @theophonchana5025 3 года назад

    x^(2) + 3x - 6 = 0
    x = (-3 + sqrt (-15)) ÷ 2
    x = error

  • @theophonchana5025
    @theophonchana5025 3 года назад

    b^(2) - 4ac = -15

  • @丹ら山工几
    @丹ら山工几 2 года назад

    Thanks

  • @jyavant
    @jyavant 8 лет назад +1

    What about for all real numbers?

  • @Chaosflyex98
    @Chaosflyex98 12 лет назад

    You are way better than my math teacher, and I wish you were my science teacher because he is just so... argh. =__=

  • @xcelpast
    @xcelpast 13 лет назад

    thanks bro

  • @universalponcho
    @universalponcho 2 года назад

    This is dope

  • @dylangarcia7314
    @dylangarcia7314 3 года назад

    if the discriminant b^2-4ac=0, the graph of f(x)=ax^2+bx+c, a not equal to 0, will touch the x-axis at its vertex? True or false?

  • @shobharanipl6129
    @shobharanipl6129 7 лет назад

    amazing

  • @ManhwaSensei
    @ManhwaSensei 4 года назад +1

    i came from art videos to this

  • @akeelahmad821
    @akeelahmad821 6 лет назад

    If there is cubic equation?

  • @kannanr837
    @kannanr837 8 лет назад

    @khan how come we get 2 parabola for a quadratic equation... won't the graph be a single parabola that meets x-axis twice...

  • @빨갱유모차길냥맘
    @빨갱유모차길냥맘 6 лет назад

    판별식이 0이라는것은 곧 2차방정식이 완전제곱식의 형태라는 것과 같네요
    잘 배우고 갑니다

  • @moonmoonmoon11
    @moonmoonmoon11 11 лет назад +1

    oh never mind!!!!!! :)

  • @ImFlamez
    @ImFlamez 6 лет назад +4

    With the internet, who needs school?

  • @moonmoonmoon11
    @moonmoonmoon11 11 лет назад +1

    how did u get 4?!!!!

  • @gkgames7589
    @gkgames7589 5 лет назад

    what if its not equal to 0 and hahs 4 numbers in the equation

  • @loversjustkeeploven
    @loversjustkeeploven 13 лет назад

    @paulceltics yea seriously. i live alone but my parents still support me. and they would have made me enlist of i didnt end the my junior year with C's.

  • @wardairfan9074
    @wardairfan9074 6 лет назад

    Can anyone give me an example of discriminant

  • @haideralikhan5976
    @haideralikhan5976 4 года назад

    love ya mate, noice

  • @peterpro9250
    @peterpro9250 3 года назад

    What if the real solution isn't rational???
    Pls tell

  • @IcedLipGloss
    @IcedLipGloss 13 лет назад

    IF ONLY MY MATH TEACHER TAUGHT LIKE THIS -____-

  • @0illuminate
    @0illuminate 4 года назад

    0 illuminate

  • @looking_33
    @looking_33 8 лет назад +1

    Why am I learning this in algebra 1 if this is algebra 2

    • @handler514
      @handler514 4 года назад

      lookinglasstie did u find your answer after 3 years?

  • @joejones7936
    @joejones7936 12 лет назад

    The discriminant of the 3rd equation is 9489.000000000002

  • @Chaosflyex98
    @Chaosflyex98 12 лет назад

    I don't have a point. My comment had nothing to with you. Now good day, sir.

  • @fabiogaming9268
    @fabiogaming9268 6 лет назад

    JOE LIKES GUYS

  • @Chaosflyex98
    @Chaosflyex98 12 лет назад +1

    Thumbs up if you have an A in Algebra I! :D

  • @HACKER-BHAVESH
    @HACKER-BHAVESH 3 года назад

    Omg 10 year ago

  • @DianaGarces216
    @DianaGarces216 3 года назад

    watching this as my parents argue so cute XoXo

  • @hansanderson8599
    @hansanderson8599 8 лет назад +1

    the third example is not a perfect square, it is 7567 and the square root of that is 86.98850499...

    • @HPatel-vf7ih
      @HPatel-vf7ih 8 лет назад +1

      There are other square roots that might go into that number. (4,9,16,25,36,49,64,81 etc.)

  • @zeyy8090
    @zeyy8090 3 года назад +1

    So no one watches this in 2021?

  • @hockeyr5
    @hockeyr5 14 лет назад

    When the discriminant is zero there is technically one solution but isn't it a double root?

  • @Chaosflyex98
    @Chaosflyex98 12 лет назад

    I'm quite surprised that you replied to me after 11 months. Smh..