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Re: M06-02 [#permalink]
Expert Reply
singhall wrote:
Bunuel wrote:
singhall wrote:
Because \(\sqrt{x^2}=|x|\). Check for more Absolute value tips: https://gmatclub.com/forum/absolute-val ... 75002.html





What is the difference between Because \(\sqrt{x^2}=|x|\) and Mathematically the square root function cannot give negative result. When the GMAT provides the square root sign for an even root, then the only accepted answer is the positive root.
I got the second explanation in a different question. https://gmatclub.com/forum/d01-183474.html

Even roots have only a positive value on the GMAT.

These two statements are creating a contradiction in my head. Can someone please help me clear the difference between these two?

Thanks!


What's causing the confusion? The square root symbol, or any even root such as the fourth root, cannot yield a negative result. Therefore, \(\sqrt{x^2}=|x|\), not simply x. This is because x can be negative, while |x| cannot.


Thanks for your response Bunuel
Okay, understood, I was confused because we were putting \(\sqrt{(y+1)^2}\) as |y+1| and not simply (y+1). Makes sense.
We can write \(\sqrt{y^2}\) as y but \(\sqrt{ (y+1)^2 } \) as |y+1| is so because y if less than -1 would yield a negative result.
Am I on the right track now?


No. The following is always true: \(\sqrt{x^2}=|x|\).

For instance, of x = 5, then \(\sqrt{x^2}=|x|=5\) and if x = -5, then \(\sqrt{x^2}=|x|=5\).
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Re M06-02 [#permalink]
I think this is a high-quality question and I agree with explanation.
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Re M06-02 [#permalink]
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