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Inequalities

by kaf » Tue Mar 24, 2009 12:12 am
Hi, Can someone please help in explaining this to me.

I saw this question in OG

1-x^2 >= 0

in the answer explanation 1-x^2 was factored to get
(1-x)(1+x)

My question is how do you factor 1-x^2 to get (1-x)(1+x)?

I would be very grateful if someone could explain this to me please.

thanks
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by nitya34 » Tue Mar 24, 2009 1:37 am
My question is how do you factor 1-x^2 to get (1-x)(1+x)?


well :)

1-x^2 =(1)^2 - (x)^2= (1-x)(1+x).
got it?
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by kaf » Tue Mar 24, 2009 1:48 am
nitya34

I still dont get how 1-x^2 =(1)^2 - (x)^2
because i am thinking ^2 affects only x and not 1

thanks
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by nitya34 » Tue Mar 24, 2009 1:58 am
a^2-b^2=(a+b)(a-b)

its elementary algebra

just multiply RHS.you will get it
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by kaf » Tue Mar 24, 2009 3:03 am
I think i get it now cos 1^2 = 1 anyway so it works it

thanks a lot
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by BlindVision » Tue Mar 24, 2009 9:17 pm
nitya34 wrote:My question is how do you factor 1-x^2 to get (1-x)(1+x)?


well :)

1-x^2 =(1)^2 - (x)^2= (1-x)(1+x).
got it?
I thought that this operation would only work if there were brackets enclosing 1 - x such as (1 - x)^2.

Glad I came across this thread to learn something new.
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