Proof by Contradiction | Explanation + 5 Examples

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  • เผยแพร่เมื่อ 2 ธ.ค. 2024

ความคิดเห็น • 57

  • @luketrebisacci2754
    @luketrebisacci2754 3 ปีที่แล้ว +66

    VERY disappointed. In the thumbnail, I was promised FIRE. I expected you to hold and bend fire while teaching me pre calculus. I am unsubscribing and disliking this video.

  • @peter4844
    @peter4844 4 ปีที่แล้ว +27

    I watched 3 different videos before coming here. Yours by far did the best explaining. I followed along with a similar problem and got my answer successfully :)

  • @melinawettstein4361
    @melinawettstein4361 4 ปีที่แล้ว +11

    i’m taking a midterm on proofs today so this video was perfect timing

  • @kingfisher7360
    @kingfisher7360 2 ปีที่แล้ว +6

    Now that was an effective video. I had almost given up, but this made it so easy. Thank you!

  • @AlulaZagway
    @AlulaZagway ปีที่แล้ว

    That simplicity in your explanation and the aura on you are gooooood...Thank you...I have subscribed

  • @loveconomics
    @loveconomics 4 ปีที่แล้ว +8

    What an amazing video. Clear and concise. Thank you!

  • @RubiMercuri
    @RubiMercuri ปีที่แล้ว +1

    thankyou so much this video helped more than i expected!

  • @LemuelYeboah
    @LemuelYeboah 7 หลายเดือนก่อน +1

    The explanation is really simple
    Thanks

  • @AshishSingh-753
    @AshishSingh-753 4 ปีที่แล้ว +3

    Hey Andrew keep it up your content heal the pain of abstraction of concept

  • @manavpatelpatel9735
    @manavpatelpatel9735 2 ปีที่แล้ว +1

    I personally love this video it was wonderful. I'm liking this video.

  • @kaniarisjad8123
    @kaniarisjad8123 4 ปีที่แล้ว +2

    this by far the most helpful video. thanks!

  • @prosperademoye7713
    @prosperademoye7713 ปีที่แล้ว

    Thank you so much this really helped me in my exam

  • @nightshade7092
    @nightshade7092 2 ปีที่แล้ว

    The chalk board sounds are so satisfying! I have my P4 A level mocks in a few hours, very well prepped but always found proof difficult, but not so much after this video! Thank you very much

  • @frederickteye
    @frederickteye 7 หลายเดือนก่อน +1

    Thank you chairman

  • @segfault1361
    @segfault1361 9 หลายเดือนก่อน +1

    The third and fourth proofs can also be proven by contrapositive

  • @axelletougouma8792
    @axelletougouma8792 3 ปีที่แล้ว +2

    You are the best 🤗🎊

  • @iraklimikadze9950
    @iraklimikadze9950 4 ปีที่แล้ว +1

    This video helped me a lot. Thanks!

  • @RS-xu1dm
    @RS-xu1dm 3 ปีที่แล้ว +1

    Is this correct for the last example? >> a^2 = 4b +2 and then a = sqrt of 4b +2. and after taking square root by plugging in values for b, a = a decimal number. Hence a is not an integer. So our assumption is not true.

  • @yamatanoorochi3149
    @yamatanoorochi3149 10 หลายเดือนก่อน

    ~(p->q) is p and ~q
    So 3n + 7 is even and n is even
    (Matches with contrapositive?)
    3n + 7 = 2k where k is any odd integer and n = 2m with m being any odd integer
    3(2m) + 7 = 2k
    6m + 7 = 2k
    7 = 2(k - 3m)
    Spz a number g = k-3m
    7=2g
    Implying that 7 is even, which is a contradiction
    Hence the original statement is true
    Would having 2 different odd integers be false?
    Thanks

  • @rigbyb
    @rigbyb 10 หลายเดือนก่อน

    Great video, thanks a lot

  • @TwoTerrificTails
    @TwoTerrificTails 4 ปีที่แล้ว +1

    SUPER helpful, thank you!!!

  • @Albaraa_Sabrin
    @Albaraa_Sabrin 5 หลายเดือนก่อน

    Brilliant 🎉

  • @AlulaZagway
    @AlulaZagway ปีที่แล้ว

    can we assume negation of p to be false and by contradiction run to be true and conclude p is false?

  • @ruantristancarlinsky3851
    @ruantristancarlinsky3851 3 ปีที่แล้ว +15

    Man you really helped me out a lot bro, you explained really well and I kinda like math a little more now😂👌

  • @christophershaba2492
    @christophershaba2492 2 ปีที่แล้ว

    i like your stuff bro and im really flexing my brain muscles

  • @hannanmulla7623
    @hannanmulla7623 9 หลายเดือนก่อน

    there may have been a small mistake in the truth table where p is F and q is T. I think (p->q) should be F. and (p^~q) should be T.

  • @MadalitsoKhoza
    @MadalitsoKhoza ปีที่แล้ว

    Well explained 👏

  • @justinotherpatriot1744
    @justinotherpatriot1744 2 ปีที่แล้ว

    Well, this was awesome.

  • @jdmoon9533
    @jdmoon9533 3 ปีที่แล้ว

    Simply amazing!

  • @takondwatanganyika5203
    @takondwatanganyika5203 2 ปีที่แล้ว

    So helpful..thanks

  • @RENCIOL
    @RENCIOL 4 ปีที่แล้ว +3

    Nice vid!

  • @kirimievansgitonga3449
    @kirimievansgitonga3449 ปีที่แล้ว

    the video was very awesome🥰🥰🥰🥰

  • @karengracebaniwat6573
    @karengracebaniwat6573 3 ปีที่แล้ว

    sir? how about using proof of contradiction, for all real numbers x, if x is irrational, the -x is irrational..

  • @swornimdangol5387
    @swornimdangol5387 2 ปีที่แล้ว

    I assume you want the proof explained in a little more detail.
    Here's what the proof says in English. Lets assume that conditions 1 and 2 hold. We use a proof by contradiction that it must be true for all n>=1.
    As with all proofs by contradiction, we assume the statement is false and then show it leads to a contradiction. So we assume there is some s for which P(s) is false. Lets pick the smallest s where P(s) is false. (We know that there must be a smallest number s where it is false, because any non-empty set of natural numbers must contain a smallest value). But we know that P(s-1) is true (because s is the smallest value where P(s) is false, and s-1 is less than s). But if P(s-1) is true, then P(s-1+1) = P(s) is true, contradicting our assumption that P(s) is false. Therefore there cannot be any s where P(s) is false.
    The s-1 finds the number immediately before the rule supposedly breaks down. But we know that if P(s-1) is true then P(s) must also be true, because of condition 2. This contradicts our assumption that the rule doesn't hold for P(s).
    Well-ordering appears explicitly when we use the fact that any non-empty collection of natural numbers (in this case the collection of natural numbers x where P(x) is false) must have a lowest number.
    More generally, the well-ordering principle states that if you consider 1,2,3 ... then this list will contain all natural numbers; there are no natural numbers that cannot be reached by starting at 1 and adding 1 repeatedly. If there were any missing numbers (ie if the set cannot be well ordered) then proof by induction would not work.

  • @jshringo77
    @jshringo77 3 ปีที่แล้ว +1

    you are the goat

  • @mushfiqshahriar6454
    @mushfiqshahriar6454 2 ปีที่แล้ว

    tnx a lot sir it really helped

  • @jehoshaphatjimmy4069
    @jehoshaphatjimmy4069 2 ปีที่แล้ว

    How can we prove my contradiction that the world is round?

  • @Phoenix-cg3hq
    @Phoenix-cg3hq ปีที่แล้ว

    that was helpful

  • @TseboLiphoko
    @TseboLiphoko ปีที่แล้ว

    Thanks bro

  • @MalkoleBG
    @MalkoleBG ปีที่แล้ว

    thank you

  • @Flux281
    @Flux281 3 ปีที่แล้ว +1

    hi, do you have videos on predicate logic ?

  • @maxhmetonxrono
    @maxhmetonxrono 3 ปีที่แล้ว

    Man GG the best ty !!!!

  • @ChrisInTheNorth
    @ChrisInTheNorth 2 ปีที่แล้ว

    I'm not sure all of these need the contradiction formulation to prove

  • @tibrummichael2715
    @tibrummichael2715 ปีที่แล้ว

    God bless you

  • @yamatanoorochi3149
    @yamatanoorochi3149 10 หลายเดือนก่อน

    Damn right I'm gonna flex em

  • @nandinireddy779
    @nandinireddy779 4 ปีที่แล้ว +2

    Awww!! So handsome i watched u throughout the video instead of listening

  • @meanderer9808
    @meanderer9808 7 หลายเดือนก่อน +1

    this is proof by contraposition

  • @hindabdullah6470
    @hindabdullah6470 3 ปีที่แล้ว +1

    انتا مُزه ي استاد

  • @shauny4596
    @shauny4596 2 ปีที่แล้ว

    but you are handsome. how is a handsome man like you became so smart ?

  • @EpicMathTime
    @EpicMathTime 4 ปีที่แล้ว +6

    This dude thinks he's fancy with his 60 fps

  • @JudithTennes-f6v
    @JudithTennes-f6v ปีที่แล้ว

    Your explanation is too fast can you slow it down please

  • @plsletmomodrive
    @plsletmomodrive ปีที่แล้ว

    wait omg why is he so hot... i dont hate discrete math as much anymore...

  • @Loots1
    @Loots1 ปีที่แล้ว

    thats a 2? nah bro thats a z lol

  • @Abhinavkumar-og3xd
    @Abhinavkumar-og3xd 11 หลายเดือนก่อน +1

    Please speak in hindi.