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Real number

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Re: Real number

by logitech » Tue Nov 11, 2008 10:18 am
gmat009 wrote:Plz. explain the attached.
I searched for this question but couldn't find.
if you have a NEGATIVE number inside an EVEN root - you are looking at an imaginary number

√-5 = NOT REAL

So all the answer choices, but 5, will yield a positive number in the equation below:

√(2-√X)
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Re: Real number

by gmat009 » Tue Nov 11, 2008 10:19 am
logitech wrote:
gmat009 wrote:Plz. explain the attached.
I searched for this question but couldn't find.
if you have a NEGATIVE number inside an EVEN root - you are looking at an imaginary number

√-5 = NOT REAL

So all the answer choices, but 5, will yield a positive number in the equation below:

√(2-√X)
Thanks
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