another math question for you all...

[funkywaggnelz]

This one is giving me a heck of a time... I just cant seem to get the right answer... Somehow, I keep coming up with 5 as my answer and I just know that can't be right... Here it is:

2 + 2

 

[peterhuang913]

Shouldn't the answer be 7?

 

[Apokalipse]

x=1
x²=x
x²-1=x-1
(x+1)(x-1)=x-1
x+1=1
since x=1
1+1=1 therefore 2=1

So to answer your question, you need to substitute 2 for 1, so that you get 1+1 = 2
then you need to substite 1 in again, and your answer is 1

therefore 2+2=1

 

[peterhuang913]

Interesting, I'll add that to my collection. Do you know the .999 = 1 one? That one's great.

 

[Apokalipse]

Interesting, I'll add that to my collection. Do you know the .999 = 1 one? That one's great.

actually, that one is true, if the 9's go to an infinite amount of decimal places.

x=0.9999999999.......
10x = 9.9999999999.......
10x - x = 9.0
9x = 9.0
x = 1.0

 

[peterhuang913]

actually, that one is true, if the 9's go to an infinite amount of decimal places.

x=0.9999999999.......
10x = 9.9999999999.......
10x - x = 9.0
9x = 9.0
x = 1.0

But there is a math rule that states that there is an infinite set of number between two numbers and that they are unique and not the same.

 

[Apokalipse]

But there is a math rule that states that there is an infinite set of number between two numbers and that they are unique and not the same.

There is an infinite set of numbers between two numbers that are not equal, yes. But if they are equal, then this is not the case.

Here's another way to think of the 0.99999... = 1

ask yourself: what is the numerical difference between 0.999999999..... and 1?

you might say: well, it's 0.000000........0001

But if there are an infinite amount of 9's, then you'll have to pass an infinite amount of zero's before you get to the one at the end. Which means you'll never get there.

So essentially, there is a 0.00000000000000000000000000000................... difference between 0.999999999999999999999999999.................. and 1

which is essentially just zero. That's zero difference between 0.9999999999............. and 1

 

[peterhuang913]

but theres that 1 stuck in the end =p

 

[Apokalipse]

but theres that 1 stuck in the end =p

which you'll never reach, because there is an infinite amount of 0's in the way.

 

[Apokalipse]

I'll show you why this proof is false:

1. x=1
2. x²=x
3. x²-1=x-1
4. (x+1)(x-1)=x-1
5. x+1=1
since x=1
1+1=1 therefore 2=1

It's at the step between 4 and 5.
line 4 is true, which you can see by substiting 1 for x

(1+1)(1-1)=1-1
=0

The problem occurs when you try to divide both sides by (x-1)

since x=1
x-1 = 0
and you cannot divide by zero.