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From: patrickJMT
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  • The mistake here is to assume that a² = b ⇒ a = √(b), when in fact a² = b ⇒ a = ±√(b):

    4 - 9/2 = -1/4 and (-1/4)×(-1/4) = 1/16

    5 - 9/2 = 1/4 and (1/4)×(1/4) = 1/16

    As you should have already learned if you've ever dealt with squares, (-x)² = (x)², even if -x ≠ x, so this means that 4 - 9/2 and 5 - 9/2 do not have to be equal for their squares to be equal (as shown above).

  • spoilers*****

    it's in the last line where he takes the square roots, everything is fine and dandy up until then but he does not follow this rule: sqrt(a+b)^2 != (a+b), it equals the square root of (a+b)^2.

    thus, the answer should be .25 = .25. otherwise, it does not work :)

  • sqrt((4-9/2)^2) != 4-(9/2).

  • I cheated and used a calculator. Every step is correct until the fourth line up from the end when he cuts out the square roots. From what I know, you should just be able to square root each side because they are equal, but apparently not in this case (:

  • maybe i have found the mistakes.. you can't cancel the square before we solve the number in the bracket first... am i right ??

  • no bro u went wrong when you added an extra 1... in the first to equations u had 6 "1"s and in the one after that you had 7 adding that extra 1 made the equation untrue.

  • You made a mistake also on (4-9/2 = 5-9/2), Isn't that UNDEFINED in calculus?? I thought that this was right until i saw that...

  • OMG so many trees killed for this!

  • @MastaChafa think about how much electricity you waste each day simply by using a computer and charging your mobile devices. i am sure the amount of pollution that results from this is way worse than the ecological impact of one piece of paper. i love it though when people complain about how much paper i use though; it makes me wonder about those people sometimes

  • @MastaChafa btw, every time someone watches, a new piece of paper is not used.

  • @MastaChafa aww quit it you leftist freak...

  • 0! or 0 factorial = 1

  • you made me watch almost all of this! @patrickjmt you're terrible

  • 4 - 9/2 is smaller than 0. thus (4-9/2)² = (5-9/2)² implies -(4-9/2) = 5-9/2 (adding a negative sign) or -4 + 9/2 = 5-9/2, and that is completely true but it doesn't show that 0=1.

  • lol i watch this video now for the first time and i can see that u have (4-9/2)^2 = (5-9/2)^2 but u cant just square root both sides like u did since 4-9/2 is a negative value that why it will be after canceling the square root -4 + 9/2 . well i am 17 and i could see the mistake clearly :p

  • that made no logical sense after he factored wrong

  • 16-34 is not = to 25-45 right?

    18 is not = to 20

  • @MsPinguinman

    He said 16-36 = 25-45

  • @MrRyanholder oh yeah sorry, did'nt notice that, my bad.

  • You can't equal something that is not the same at all. The equation would not make sense therefore this defies the laws of simple arithmetic which makes everything wrong. Every calculation that man made since simple calculators made to calculate is wrong. If that is wrong, then the stocks are wrong, the laws of gravity are wrong (Newton's Laws), every number is wrong that will tear a rip in the universe with a 4th dimensional figure that we don't know it exists which makes reality cease to exist

  • @Slick1681 I think thats where lag was created o:

  • when you take the square root, the resultants aren't just positive but both positive and/or negative which require the 4 proof equations to be checked before the final answer(s) ie +x=+y , +x=-y , -x=+y, -x=-y

  • Comment removed

  • fail-.- (4-9r2) doesnt event = (5-9r2) so how can cancel the square like that -.-

  • i just got mind fucked by all of you.....*head explodes*

  • Basically on the last step when you have an expression squared such as what he has

    x^2=y^2, and when you take the square root of both sides, the new equation is actually the absolute value of each expression so when you square root both sides you are left with IxI = IyI and that gives you I 4-9/2 I = I 5-9/2 l....then you get I-1/2I = I1/2 I....which is 1/2 = 1/2...and that's it. :D

  • It's like you mentally destroyed my sense of reality? Inception much?

  • you are such a cutie!

  • square root x^2=+/- x

  • u can't square root (5-9/2) with a square for (4-9/2)

  • well the thing is that 4<9/2 so 4-9/2<0 so u cant actually take the sqrt of that

  • @dajakesta1234 u are wrong there~ they do not take the sqrt of 4-9/2 but (4-9/2)^2. u see here the square makes the figure positive.. the actual mistake there is when he/she just simply take sqrt without the ±..so the answer would be ±0.5=±0.5...

  • @impiankuIMPIANKU dude that is definitely not really the major wrong thing the wrong thing is √ab=√a√b is applicable when a>0 and b>0 but one side had a>0 b>0 but on the other it had a<0 b<0 which should mean that |a+b|= √(a+b)²

  • @lirenyeo well if you werent illiterate and you read the TITLE, you would see that this video is mostly a joke.

  • @bdiddy77777

    I find it funny that you forgot the apostrophe in "weren't" while insulting his literacy.

    That is all.

  • squareroot of a number gives you 2 solutions.

    eg.

    sqrt(4) = +2 & -2

  • 1:54, what happened to that 4?

  • Adding more numbers is the trick to make from 0 to 1

  • The two things you need to look out for in these kind of problems is dividing by zero or taking an even root of a negative number, because neither is allowed (unless you use i). I didn't notice him dividing in this, so let's look at the latter statement. Well towards the end he takes a square root (which is an even root) of both sides. the quantities that he takes square roots of are 4-(9/2) and 5-(9/2). 4-(9/2)=-0.5. This is negative and cannot be square-rooted, so there's the problem...

  • @GME777Gregz ... Sorry, i just realised that the quantities were squared, which gives (-0.5)^2, which is positive. But i'm still very reluctant to accept that it's to do with the +/- generated when the square root is taken, because wouldn't that give a result of (+/-)x = (+/-)x, x=(-/+)(+/-)x=(+/-)x, giving one answer that is correct, but another that still gives |x|=|x|, which is not the way the answer turned out. Nice problem though, got me thinking. Thanks Patrick.

  • @XPhantom18 I'm over-simplifying here, but think of it as +/- = -/+

  • @ExtensionChord thats an easy one ... only stupid doesnt know it

  • alright, im gonna write this down on the whiteboard in my college classes and let the students crack their brain about it. haha!!

  • take this junk down! its wrong!!!!!!!!

  • @lifeshortsostandtall That's the point.

  • (4-9/2)^2 = (-1/2)^2 = 1/4

    (5-9/2)^2 = (1/2)^2 = 1/4

    However, x^2 = y^2 implies that |x| = |y|, not that x = y. You can take the square root of a negative number, but it produces an imaginary number. However, that doesn't change the fact that !(x^2 = y^2 -> x=y). The perfect example:

    (-1/2)^2 = (1/2)^2

    does not imply that:

    -1/2 = 1/2

    but instead that:

    |-1/2| = |1/2|

    1/2 = 1/2

    which implies that 1=1 and 0=0

  • This is similar to the proof that 2 = 0:

    e^ipi = -1

    e^2ipi = 1 = e^0

    2ipi = 0

    2 = 0

    [Fucking youtube wont allow me to post this alone because they think this is a spam message or something...]

  • because square operation isnt reversible

    although x=y implies x^2=y^2 but

    x^2=y^2 doesnt imply x=y

    basic algebra but thats what most north american doesnt learn in grade 6

  • I thought I knew math...

  • Well i think 1st part of the error there is 4^2 - 2*4*9/2 + 9/2^2 go to (4-9/2)(4-9/2), that's incorrect. Because 2*4*9/2 is from 36, if split it, it's no longer = 36.

  • @jasonyck2010 I'm sorry, that part is completely correct do the math with a calculator.

  • thought u would trick me and im just 13 lmfao nice try

  • dumbfucks!!!!

    dont know where to cancer the square root!!!!

    learn the basics first

  • @archerjeffry yes you fools, make sure to cancer the square root.

  • @patrickJMT hello you should not cancel the square roots or denominators when they are 0

    i think u did in your video thats why u got wrong

    but scientists are never wrong

    any way  there are are so many ways to prove that 0=1 by applying the normal rules but we are supposed not to use them in the sensitive cases

    thanks lolzzzzzzzzzzzzzzzz

  • @patrickJMT those square roots are gonna die cuz they have been smoking......

  • @patrickJMT patrick, are you a comedian? that's the funniest comeback ever. this comment is worthy of being on t-shirts!!

  • @archerjeffry im pretty sure someone has to learn his (1) manner and (2) spelling before asking others to "cancer" their sqrt.

  • + or - when you square root

  • Lol, nice one. The error is ofc on the square root y^2=x, y=+sqrt(x) if y>0 and y=-sqrt(x) if y<0. In this case (4-2/9) < 0 which yields (4-9/2)=-(5-2/9) , 0.5=0.5 that is obviously true.

  • the real mistake is, you cant square root (4- 9/2) because it is a negative number inside the brackets.

  • u see on 3.03 he squares the thing and then he square roots the thing... the mistake is there... he should understand that he is doing the square root of (4-9/2)^2 therefore the order of mathematical calculation tells us that we have to solve anything within the parenthesis before doing any other things... so it bcm (-0.5)^2 = (0.5)^2 which implies 1/4 = 1/4 and the root of 1/4 = 1/2... he kenot just take the ^2 away before squaring it... LOL

  • You completed the square wrongly

    You have two seperate equations on each side that are equal to each other. once you completed one side you have to complete the other side using THOSE numbers the differnce being the 4 and the 5

  • The second step you made on the new sheet was the lie. There is no rule that says if X^2=Y^2 then X=Y. This rule is provably false; if X is a negative number and Y is it's positive counterpart, then even if they square to the same number they themselves are different. For example, (-1)^2=(1)^2, because both -1 and 1 square to 1, but -1=/=1.

    In this case, the fact that (4-9/2)^2=(5-9/2)^2 does not imply that 4-9/2=5-9/2. 4-9/2=-1/2, and 5-9/2=1/2.

  • @Hooya2 I was thinking along those same lines, and even did it....by making one root negative and the other positive, it worked out beautifully

  • @Hooya2 I agree with you, this is because a square root has 2 Values!

  • Comment removed

  • @Hooya2 @Hooya2 that's exactly it. the problem here is that no rule addresses this issue. but what he did is still right because:

    let (4-9/2) =n.

    n*n = n^2

    therefore, (4-9/2) (4-9/2) = (4-9/2) ^2

  • @Hooya2 What the fuck did you just say...?

  • @mane521 Go to school, dumb shit.

  • @MegaMusicNote no need to be mean.

  • @mademan39 people are nuts on the internet

  • @XPhantom18 Yes you can. It is an equality so it is legal as long as you do it to both sides.  The problem is what happens when you take the square root (I don't want to give it away because you might still be working on it.)?

  • can't forget about +/-

  • (4 - 9/2) is a negative number, so you can't square root it.

  • The mistake is at the fourth last step. You can't square root both sides like that. That's incorrect.

  • just remember that when you wanna sqt root both sides, you cannot assume the result is always positive. Result can be negative or positive...

  • Mistake is algebric in nature. x^2 - 2xy + y^2 = (x-y) (x+y)

    When he factorised it, he put made it into (x-y) (x-y)

    where x= 4 or 5 on left and right side of equation and y= 9/2.

    Basic algebra.

  • @KouzukeRan (x-y) (x+y) = x^2 - y^2

  • @KouzukeRan no, the formula is x^2 - 2xy + y^2 = (x-y)^2

  • @An3ID

    yea, sorry, made a mistake. haha, was too tired. realised it after i posted, but then i was heading to bed, so... :P

  • @KouzukeRan but these are the stuff we learn in middle school....

  • lololol :P

  • Hahaha, cool !

    Feel sorry a bit for the lonely one that noticed this.

    Then again, I collect stamps :-)

  • here's the problem i cant figure out.....

    0 raised to any power is 0. any number to the power of 0 is 1... so what is 0 to the power of 0?

  • @boxmailman it depends on who you ask, unfortunately. For the sake of simplicity, it's commonly accepted that zero to the zero power is equal to 1. Some argue that it, like dividing by zero, should remain undefined.

  • @boxmailman 1 not 0 sorry.

  • When I read the title, I was expecting the sums involving 1,0 and infinity.

  • When you removed the square, you should have taken the absolute value of both sides. Then you get 0.25 =0.25.

    You'd be better off to show that the sum of 0 is equal to 1 or negitive one, bit more interesting.

  • Comment removed

  • Comment removed

  • obviously the problem is with the square root, it has to be + & - on both sides, not just +.. but it was a good distraction. (y)

  • lmfao, you're so funny... :l

    you make my nights at the library, thank you! :)

  • You incorrectly used PEMDAS in this video.

  • lol. you square it and get Plus or Minus...just like you do with any y=function....like a circle function, no? minus "function" on the left. positive "function" on the right. and they equal

  • actually, its over 9000.

  • :)  4 .. 9/2^2 < 5 .. 9/2^2

  • Yeah, (4-9/2)= -0.5 while (5-9/2)=0.5 and there it's where it's gets wrong. -0.5≠0.5.

  • 4^2 -4.9 =/= 5^2 - 5.9

    the answer are different

  • @ExtensionChord that is also a good problem!

  • noob! L2sqrt proper :D

  • The error is in the square root. You will get

  • sqrt(x^2) is actually |x|

    so in this case you should write |4-9/2|=|5-9/2|

  • I like this "fun" little videos.

    Keep it up~

    :D

  • @ivanxdxd2008 He posted this as an exercise. (Can You Spot the Mistake?) is right in the title. No one actually believes that 0 = 1, but it's fun to find where the error came from. You should calm down. You're not as smart as you think

  • @ivanxdxd2008 Calm down. It's all in good fun.

  • What?

  • Key observation: sqrt((1/2)^2) is equal to plus or minus1/2, not just 1/2.

  • took the square root wrong? need both positive and negative values.

  • Comment removed

  • isnt the mistake in the factoring where you had the brackets and one should have been a plus and the other minus??

  • @patrickJMT I enjoyed that. I guessed early on the mistake might be one which used to happen to me all the time - not accounting for the + AND - sqrt of a number.

    And in the sqrt step the LHS should become the -sqrt and the RHS should become the +sqrt.

    

  • @patrickJMT I have a question though. Without getting to the end and realising the LHS doesn't equal the RHS, and with no real life context such as the velocity of a falling object is down, **how can we know it is the -sqrt of the LHS which equals the +sqrt of the RHS? **

  • @TheKCure: 81/4 = (9/2)²

  • these videos are fun! keep them coming!!

  • @1brixian:

    Which negative square root?

    You're taking the square root of a squared number (which is always positive).

  • @someonep93 I think you have to square the number 4-9/2 ( that is negative) first before you take the square root of it. You can't have a negative base under square root....hope this makes sense

  • @someonep93 or you take the absolute value of it..and put a - sign in front of the number if it is negative

  • 81/4 doesn't reduce to 9/2 but 40.5/2.

  • @TheKCure yes 81/2 would reduce to 40.5/2 if you were dividing by 2 however he was taking the square root. @Oscarfeliciano is in fact correct.

  • should have put "QED" at the end....

  • yep,can't square root a neg number

  • let the rage commence

  • @commanderkool868 at least people are not spazzing out like the comments in the other video!

  • @patrickJMT *crosses fingers* :)

  • When you get to the point of (4 - 9/2)^2 = (5 - 9/2)^2, you need to solve the parenthesis at both sides of the equality first, and then handle the squared at each side. It is a mistake of handling the order of operations wrongly.

  • Why do you hate me patrickjmt? The last problem consumed my life for three days and now another one. haha

  • @kx32ta1 i think they are just fun little problems. : )

  • @patrickJMT Thanks for making math fun. Keep them coming

  • (4-4.5) is negative and (5-4.5) is positive but both square to be 0.25 and both root to be plus or minus a half.

  • plus minus when you take the square root, :)

  • The error lies in the end part. Everything you did up until then is fine, and is actually correct. The problem is, when you multiply a number by itself, it gives one answer. When you square root it? You get two answers. This is because there are two ways to multiply a number such that it becomes positive. So (4 - 9/2) also equals (-5+9/2) which both are equal to -.5. This makes sense because if you square that you get .25 which is (81/4)-20.

  • Troll math

  • Well i think you just went too in depth. Im used to simplifying my answers, not complicating them.

  • (4 - 9/2)² is a number, not an expression. squareroots of a number have one answer. Also, o-r-d-er of o-p-e-r-a-t-i-o-n-s!

    (-0.5)² = 0.25, (0.25)^0.5 = 0.5

    Sorry if my message is double. Don't know if youtube got it the first time.

  • At the begining, Isn't it incorrect to add seperate numbers to the equation? what I mean is since you added 16 to one side, don't you have to add 16 to the other side instead of a 25? That seems to be where the mistake is at since you did the same with the (81/4) but you added it to both sides, hence Adding the same value to both sides of the equal sign.

  • @DThundertower no, you've missed the point.

  • Hahaha I'm pretty sure he knows that one doesn't ACTUALLY equal to zero guys

  • @tlawaw thanks for the vote of confidence :)

  • LOL Cool

  • absolute value have to be taken into consideration. you cannot simply cancel the square roots sir. youre argument have failed once again =)

  • here's a try, it's got to do with the negative square root

    (4-9/2)^2=(5-9/2)^2

    (4-9/2)=+-(5-9/2) taking square root gives both the negative and positive values

    4-9/2=5-9/2 => 4=5 solving for the positive value and discarding it

    4-9/2=5+9/2 => 4+5=9/2+9/2 => 9=9 solving for the positive value

  • @muzammilali007 y do u discard 4=5? i dont get that part

  • @arcinfol think of it as a function that is not valid for a certain value (in this case the negative value). the problem arises due to the even power as it turns negative vales into positive(even function) so we can't tell whether the input was positive or negative so we consider both and then check whether the function is valid for the answers we get or not.

    if you try to solve this problem with cube root or any odd root you won't face this +- confusion you face with the squareroot or evenroot

  • you sir have FAILED!!!!!

  • When you take the root of a square you have to take the absolute value im pretty sure...

  • My mind might be blown...yes, but on the positive side let the dividing by zero commence. The answer is undefined no longer. ha my professor is going to love me

  • study = nofail

    nostudy = fail

    study + nostudy = nofail+fail

    study(1+no) = fail (1+no)

    study = fail

  • @arlihama

    girls = (time)(money)

    time = money ,therefore

    girls = (money)^2

    money = evil^(1/2) ,

    girls = [evil^(1/2)]^2

    girls = evil

  • @roadster9k "Money is the root of all evil." Haha, good job. :)) Though I'm a girl, I like what I'm seeing.

  • @roadster9k mu me ley bhen chod!!!

  • (4-9/2)*1/2 can not in this case reduce to just (4-9/2), it MUST reduce to -(4-9/2)

  • How abt my theorem: According to the law,anything divided by zero is Infinity.

    So 1/0=Infinity

    therefore, 1=Infinity*0

    But, Anything multiplied by zero is zero.

    Therefore, 1=0.. :)..haha..

  • @MrinalChoudhary 1/0 is technically undefined isn't it? Contradiction is on the first line - 1/0 != infinity.

  • @Adam9172 its undefined because it goes to infinity..1 cannot be equal to 0..but there are several methods of making it appear so..one such is mine..:)

  • @MrinalChoudhary yes, but that's my point - infinity is, by it's very definition, undefined. Therefore you can't say 1/0 = infinity, because both sides equal infinity, if you catch my drift.

    I'm glad you're not being too serious about this, at least :) People who are too serious about this just don't realise that if this were the case, computers etc wouldn't work! :p

  • @MrinalChoudhary Uz needz to wentz seez limitz an shtuffz kz?

  • @raydredX wtf are u talking abt??..learn English Bitch.

  • @MrinalChoudhary I'm sorry. I've been told I will never be able to learn English. Also why did you cap the "B" on bitch, if I may ask?

  • @raydredX because I like my Bitches with Big B..if u know what i mean..;)

  • you lost me at -20= -20. :)

  • To extend the proof that 0 = 1, multiply both sides to get 0 = a, then from the original equation multiply each side by b, so 0 = b. If 0 = a and 0 = b, that means a = b and every number is equal to every other number! CRAZY