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possible values of x ?

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by tohellandback » Fri Jul 31, 2009 7:04 pm
x^2-2<0
X^2<2

-sqrt(2)<X<sqrt(2)
The powers of two are bloody impolite!!
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by pandeyvineet24 » Sat Aug 01, 2009 4:07 am
C should be. for any x greater than sqrt(2) and any x less than (-sqrt(2)) the equation will hold good.
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by crackgmat007 » Sat Aug 01, 2009 5:27 pm
tohellandback wrote:x^2-2<0
X^2<2

-sqrt(2)<X<sqrt(2)
Squaring on both sides of inequality, I got X<sqrt(2). I am not clear about -sqrt(2)<X. Can someone explain this pls?
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by tom4lax » Tue Aug 04, 2009 5:08 am
When you take the sq root of a squared variable, you need to take into account that the answer could be positive or negative, so take the absolute value:

x^2 < 2
abs(x) < sqrt2

x < sqrt 2 and -x < sqrt 2 or x > -sqrt2

ans. is C
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