Reverse Triangle Inequality Proof

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  • Опубліковано 31 тра 2015
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    Reverse Triangle Inequality Proof. A very careful proof of the Reverse Triangle Inequality for real numbers.

КОМЕНТАРІ • 54

  • @wii3willRule
    @wii3willRule 5 років тому +32

    You're close to the only "math help" channel I've found for introductory real analysis. Thank you so much for existing.

  • @caitmaureen9960
    @caitmaureen9960 7 років тому +29

    Is the Reverse triangle Inequality not ||x|-|y||

  • @lolXDrofl
    @lolXDrofl 9 років тому +9

    Thank you! This was very helpful, and well explained, thank you for sharing!

  • @raghavahuja7284
    @raghavahuja7284 8 років тому +9

    it was really the obvious part that wasn't obvious to me. I didn't think of using the definition of absolute value to justify the final result.

  • @alikariananda6149
    @alikariananda6149 3 роки тому +3

    thank you so muchhhhhh, you helped me understand this inequality and I able to finished my homework 🔥 (subscribed!)

  • @becomepostal
    @becomepostal Рік тому

    What about complex numbers or vectors?

  • @KazACWizard
    @KazACWizard Рік тому

    couldnt you also say: that mod(b) is less than or equal to mod(a) for that mod(mod(b)-mod(a)) be greater or equal to 0. hence mod(b)-mod(a) is greater or equal to zero but mod(b)-(mod(a)) is greater or equal to mod(a+b) but if that holds then mod(a+b) is greter than zero and hence taking mod of both sides leaves the lhs equal to mod(a+b) since mod of a number always positive doesnt change the number? thats alteast my thought process i may be wrong

  • @griffinwright5583
    @griffinwright5583 5 років тому +13

    This would be more helpful if it was the actual Reverse Triangle Inequality. (| |x| - |y| |

    • @kittenluvzu
      @kittenluvzu 3 роки тому +2

      Yeah, the guy loses credibility when he sets off the prove the wrong thing.

    • @GundoganFatih
      @GundoganFatih 3 роки тому

      ||x-y|| =? ||y-x|| this should be stated to complete the proof

    • @darrenpeck156
      @darrenpeck156 2 роки тому +2

      Just insert - b then the right hand side is |a+-b| = |a-b| as you wanted

  • @joewrose
    @joewrose 3 роки тому +1

    You're my hero m8, this was miles better than my lecturers.

  • @mahmoudalbahar1641
    @mahmoudalbahar1641 3 роки тому

    Many thanks for this good video.

  • @LyricalCom-co9xj
    @LyricalCom-co9xj 3 роки тому

    Sir I wanna asked u one question plzz

  • @muradalm5730
    @muradalm5730 4 роки тому

    i would buy you a beer.. You are a true hero!
    new sub here!

  • @thrishnapavithran8583
    @thrishnapavithran8583 Рік тому

    Thank u... excellent video

  • @darrenpeck156
    @darrenpeck156 2 роки тому +2

    Excellent video of a fundamental property

  • @user-ur5xi3lv1i
    @user-ur5xi3lv1i 6 місяців тому

    The Math Soucerer Once again saving my life bro your the GOAT of math

  • @princeardalan
    @princeardalan Рік тому +1

    Can you please refer me to an official source that uses the phrase 'reverse triangle inequality'?

    • @TheMathSorcerer
      @TheMathSorcerer  Рік тому +1

      The term Reverse Triangle Inequality often means similar things written different ways.
      Another way is:
      ||x| - |y||

    • @TheMathSorcerer
      @TheMathSorcerer  Рік тому +1

      I "think" this version appears in the book by Fitzpatrick on Advanced Calculus. I don't have it with me here to check, but pretty sure it's there. Hope this helps:)

    • @princeardalan
      @princeardalan Рік тому

      @@TheMathSorcerer I have the 2nd international edition of that book and I can't find the phrase 'reverse triangle'. My supervisor said I am not allowed to use this phrase for that inequality unless I can show him a source that uses this phrase. I am surprised to find out none of the books I have actually use this phrase...

  • @haticeavsar4704
    @haticeavsar4704 3 роки тому +2

    Your voice is so relaxing and, this video is the best between triangle inequality proofs. You literally saved my life

  • @LyricalCom-co9xj
    @LyricalCom-co9xj 3 роки тому +1

    I searched more than half hour in internet to get this problem,now finally here I get

  • @bhumikachaudhari835
    @bhumikachaudhari835 2 роки тому +1

    Thanks a lot...why couldn't i think of this...

    • @TheMathSorcerer
      @TheMathSorcerer  2 роки тому

      It’s hard to do on your own the first time👍

  • @miriamfox4489
    @miriamfox4489 Рік тому +1

    Thanks!

  • @saramezrig3355
    @saramezrig3355 4 роки тому +1

    You really saved my life👌🏻going

  • @MuhammadIsmail-un3qd
    @MuhammadIsmail-un3qd 3 роки тому

    If |x|< a and |y|< b then |x| + |y| < a + b.
    Sir! Can you make a video on it's proof? Is this true generally?
    Of course a,b>=0

  • @slashda5521
    @slashda5521 3 роки тому +1

    Absolute savior thanks bro

  • @juarjuna4130
    @juarjuna4130 5 років тому +2

    What a calm voice. Thanks !

    • @TheMathSorcerer
      @TheMathSorcerer  5 років тому +1

      thanks!!

    • @juarjuna4130
      @juarjuna4130 5 років тому

      You are welcome! I hope you could make a video about proofs on subsequences (Advanved Calculus).

  • @Maths_Magic_
    @Maths_Magic_ 2 роки тому +1

    It really helped👍👌

  • @oukkalyacine3051
    @oukkalyacine3051 3 роки тому +1

    thank you man you are my hero

  • @TheMathSorcerer
    @TheMathSorcerer  9 років тому +2

    • @SimchaWaldman
      @SimchaWaldman 8 років тому +22

      +The Math Sorcerer
      I thought |a - b| ≥ | |a| - |b| | is the reverse inequality.

  • @bobmarley9905
    @bobmarley9905 Місяць тому

    Its cool how you could also prove this using the same exact technique done in *your* video for the regular triangle inequality (for real numbers): ua-cam.com/video/lj765RaxreE/v-deo.htmlsi=QhhZV4GR7snVQceN

  • @Schoolthesefools
    @Schoolthesefools 3 роки тому +1

    life saver

  • @GundoganFatih
    @GundoganFatih 3 роки тому

    | |x|-|y| |

  • @user-jg6ly3ep1x
    @user-jg6ly3ep1x 5 років тому

    save my life