0=2, math inside.

[benylor]

Lets not start this again.

Almost as bad as the infamous 0.9 repeating = 1 thread.

I hate whoever decided infinite 0.9 = 1. By that logic you could say that every number is the same.

No you can't. You can, however, say that 0.9r = 1. Analysis 1101, convergence of series.

The error in the TC's math is, as mentioned earlier, that there are two possible square roots, the positive and the negative.

 

[benylor]

Call me crazy, but unless my calculator shat itself, cos(pi) does not equal -1, and Sin^2(pi) does not equal 0.

Radians, dude, not degrees.

 

[USSR]

Lets not start this again.

Almost as bad as the infamous 0.9 repeating = 1 thread.

I hate whoever decided infinite 0.9 = 1. By that logic you could say that every number is the same.

I feel your idea is mislead.

I don't feel the need to explain it to you so go look it up.

Or find that 0.9 repeating thread.

Tehe.. *Bud dum tish*

 

[Asturiel]

You can get numbers to say anything if you do it right. For example.

X=Y+1
Y=X+1
X=5

In order to solve for Y use Y=X+1

Y=5+1
=6

But isnt X 5? Lets test that.

X=Y+1
5=6+1
5=7 Wadya know Im a math genius! 5=7 people!

 

[Rand-m]

Call me crazy, but unless my calculator shat itself, cos(pi) does not equal -1, and Sin^2(pi) does not equal 0.

Radians, dude, not degrees.

And this is why I will fail my math exam terribly. Thanks for the reminder that I should get back to studying.

EDIT:

X=Y+1
Y=X+1

But based on the first equation, Y would equal X - 1...

Alright, back to studying. Sorry again about the "the calculator shat itself" comment.

 

[The Cheezy One]

Lets not start this again.

Almost as bad as the infamous 0.9 repeating = 1 thread.

ah yes
what was it?
(rec) = recurring
0.9(rec)x10=9.9(rec) A
0.9(rec)x1=0.9(rec) B
A-B = 9
9/9(because one of the 10 0.9(rec)s has already been taken off) = 1

somthing like that

what this proves is that to all extents and purposes, any number with a recuring decimal is equal to rounding the final (theoretical) decimal to its nearest multiple of 5
so 0.9(rec) is theoretically = 1, as there is nothing you can do with 0.9(rec) that you cant do with one
however 0.9(rec)=/=1 or rather 0.9(rec)=1, but 1=/=0.9(rec)
its like saying you can use a tree as a bridge, but a tree =/= bridge
but this is all theoretical, as decimals dont really exist

im specail!

 

[yoyo13rom]

First off, this particular proof is search bar approved, and does not contain division by zero.

cos[sup]2[/sup]x=1-sin[sup]2[/sup]x.........................Given
cos x = (1-sin[sup]2[/sup]x)[sup]1/2[/sup]................Square root each side.
1+ cos x = (1-sin[sup]2[/sup]x)[sup]1/2[/sup] + 1....Add one to each side
1 - 1 = (1-0)[sup]1/2[/sup] + 1..................Evaluate at x = pi (3.14159...)
0 = 1 + 1
0 = 2


So where is the error?

EDIT: I probably should expand, I am trying to find the error, I am not posing this as trivia.

cos x = (1-sin[sup]2[/sup]x)[sup]1/2[/sup] Right here my good friend!
cos x =(-1,1)
but cos[sup]2[/sup]x=(0,1)
You can't extract the square root because cos[sup]2[/sup]x might be something negative multiplied with something negative(you don't know for sure if this is the case).
In any case the square root of cos[sup]2[/sup]x= +cosx(if it's positive) or -cos x (if cos x is negative)

 

[klakkat]

Sorry to spoil your fun, but
(1-(sin(pi))^2)^1/2 = 1 or -1 (the same goes for the root of any other number)
therefore the resultant equation may also be
1-1 = -1 + 1
which is simplified into 0 = 0.
now that makes more sense

This is the correct explanation. Keep in mind whenever taking a square root you get that pesky +/- out front, which means the correct solution uses either the positive or negative of the numerical value of the square root, not necessarily both.

Also, for mathematical cleanliness, there was no point to adding 1 to both sides; actually, it may have obscured the error.

 

[Velocity Eleven]

if 0 = 2
0x = 2x
0 = x
sub in (x = 0) to (0x = 2x)
0(0) = 2(0)
0 = 0

problem solved

 

[CuddlyCombine]

First off, this particular proof is search bar approved, and does not contain division by zero.

cos[sup]2[/sup]x=1-sin[sup]2[/sup]x.........................Given
cos x = (1-sin[sup]2[/sup]x)[sup]1/2[/sup]................Square root each side.
1+ cos x = (1-sin[sup]2[/sup]x)[sup]1/2[/sup] + 1....Add one to each side
1 - 1 = (1-0)[sup]1/2[/sup] + 1..................Evaluate at x = pi (3.14159...)
0 = 1 + 1
0 = 2


So where is the error?

You can't root cos[sup]2[/sup]x by just removing the square of cos, since you're treating sin[sup]2[/sup]x as one element.

 

[Davey Woo]

I'm sick of these now.
2 does not equal 0.
2 equals 2.
EDIT:
To sort of prove my point.

0=2
0+2 = 2

 

[karmapolizei]

You can get numbers to say anything if you do it right. For example.

X=Y+1
Y=X+1
X=5

Of course you can. You can make math say all kind of bollocks if you use contradicting equations. (That was so painfully obvious even I got it.)

 

[Hazzaslagga]

I don't think this works but we were taught a way to make 1=2 or possibly the other way around by using reccurring numbers ie 0.9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999 etc...

 

[Kazturkey]

First off, this particular proof is search bar approved, and does not contain division by zero.

cos[sup]2[/sup]x=1-sin[sup]2[/sup]x.........................Given
cos x = (1-sin[sup]2[/sup]x)[sup]1/2[/sup]................Square root each side.
1+ cos x = (1-sin[sup]2[/sup]x)[sup]1/2[/sup] + 1....Add one to each side
1 - 1 = (1-0)[sup]1/2[/sup] + 1..................Evaluate at x = pi (3.14159...)
0 = 1 + 1
0 = 2


So where is the error?

EDIT: I probably should expand, I am trying to find the error, I am not posing this as trivia.

Where did your sin[sup]2[/sup]x go?

 

[Turbulence]

You can get numbers to say anything if you do it right. For example.

X=Y+1
Y=X+1
X=5

In order to solve for Y use Y=X+1

Y=5+1
=6

But isnt X 5? Lets test that.

X=Y+1
5=6+1
5=7 Wadya know Im a math genius! 5=7 people!

How do you justify these two?

X=Y+1
Y=X+1

That just makes no sense.

 

[gim73]

Okay, here is your problem. Cos^2(x) =/= (Cosx)^2. What you were doing was saying EXACTLTY that. You pretty much made a fallacy like saying cos(x) + cos (x) = cos (2x).

 

[dont_blink]

... i answered this but my maths confused me so i deleted it... i think i did it wrong anyway...

 

[Auron225]

i remember believing 0.9 = 1 for a while, told it to a friend - he was VERY baffled - then he came in the next day and proved me i was wrong =) i was happy to be wrong! i thought maths had betrayed me!

someone once thought they had found an error in maths with pythagoras. he labeled each side as X, so that X^2 = X^2 + X^2, so that X^2 = 2X^2! lol noob - if the opposite and adjacent are X, the hypotenuse cannot = X
=P

 

[shroomz]

Okay, here is your problem. Cos^2(x) =/= (Cosx)^2. What you were doing was saying EXACTLTY that. You pretty much made a fallacy like saying cos(x) + cos (x) = cos (2x).

Depending on your notation cos^2(x) and (cosx)^2 are the same