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by jayhawk2001 » Sat Aug 04, 2007 2:51 pm
The sqrt of a number cannot be negative. We are given x < 0 and so
answer has to be -x (which is a positive number).
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by beny » Sat Aug 04, 2007 6:25 pm
Are you sure this is a GMATPrep question...? GMAT does not use imaginary numbers.
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by jayhawk2001 » Sat Aug 04, 2007 6:44 pm
beny wrote:Are you sure this is a GMATPrep question...? GMAT does not use imaginary numbers.
Can you please clarify on what the imaginary number is in this case.

-x|x| is positive when x<0. So, we are not trying to take the
square-root of a negative number to get an imaginary number.
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by givemeanid » Sun Aug 05, 2007 6:38 am
The sqrt of a number cannot be negative.
Every positive number has TWO square roots. One positive, one negative.

36 = 6*6 = -6 * -6
sqrt(36) = 6 or -6
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by jayhawk2001 » Sun Aug 05, 2007 8:59 am
givemeanid wrote:
Every positive number has TWO square roots. One positive, one negative.

36 = 6*6 = -6 * -6
sqrt(36) = 6 or -6
Actually let me make a small distinction --

If x^2 = 36, you can say x = +6 or x = -6

If you are asked to find sqrt(36), there is only 1 root and that is +6.

I learnt this important concept through this forum. Please check https://www.beatthegmat.com/viewtopic.php?t=2183
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by chatekar » Sun Aug 05, 2007 9:51 am
jayhawk2001,

I'm totally confused. First of all I haven't clearly understood the explanation for my question.
And the other thing, I don't understand why sqrt(36) is always 6?

Thanks
Suhas
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by givemeanid » Sun Aug 05, 2007 12:21 pm
Actually let me make a small distinction --

If x^2 = 36, you can say x = +6 or x = -6

If you are asked to find sqrt(36), there is only 1 root and that is +6.

I learnt this important concept through this forum. Please check https://www.beatthegmat.com/viewtopic.php?t=2183

From the thread you linked to: "Every positive number n has two square roots, one positive and the other negative, but root-n denotes the positive number whose square is n".

Son of a *#$@%. Completely missed that. Thanks buddy.
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