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Square Root


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On a semi-related topic I once belived all of mathmatics was out by +1 because

 

(n - 1) * (n + 1) = (n * n) + 1

When you were a child right?

Well anyways, what you've written there doesn't seem to be right since the difference of two squares: [math]a^{2}-b^{2}=(a+b)(a-b)[/math]

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My simple proff that my rule is right,

and yes it was when I was a child I descovered it.

 

You're not expanding, that's why you're getting the incorrect result. You are familiar with expanding and the inverse...factorising ?

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  • 1 month later...
There, still proves its all of by -1

 

It doesn't prove maths is 'all' out by -1, because 4*4 and (4-1)(4+1) are not equivalent.

 

Expanding is just...(4-1)(4+1) so 4*4=16, 4*1=4, 1*(-1)= -1, 4*-1= -4

 

16+4-1-4=15

 

So your results are right, but your reasoning to why the results are different is wrong. My first post was in response to your first calculation, sorry I missed the second.

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(4 - 1) * (4 + 1) = 15
     (4 * 4) - 1 = 15
           4 * 4 = 16

 

There, still proves its all of by -1

 

So, you can't understand why (n2-1)!=n2? I seriously don't see the problem here.

 

(n+1)(n-1)=n2-1, not n2. Watch, I'll FOIL it for you.

F(first terms multiplied together)+I(inside terms multiplied together)+O(outside terms multiplied together)+L(last terms multiplied together)

(n+1)(n-1)=n2+(1)n+(-1)n+(1)(-1)=n2-1

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