## Y=X^1/2 is the same as Y=+/-sqrt(X) ??

1. The problem statement, all variables and given/known data

This is from a textbook:

Y=X^1/2 is the same as Y=+/-sqrt(X)

2. Relevant equations
3. The attempt at a solution

100^1/2=10

How is 100^1/2=-10 also true?

Thanks.
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hi solve!
 Quote by solve This is from a textbook: Y=X^1/2 is the same as Y=+/-sqrt(X) 2. Relevant equations 3. The attempt at a solution 100^1/2=10 How is 100^1/2=-10 also true? Thanks.
you're right, it's wrong!

(which book?)

 Quote by tiny-tim hi solve! you're right, it's wrong! (which book?)
Thank You for the answer, tiny-tim.

As for the book, I dont wanna name it and make the otherwise excellent textbook look bad.

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## Y=X^1/2 is the same as Y=+/-sqrt(X) ??

 Quote by solve Thank You for the answer, tiny-tim. As for the book, I dont wanna name it and make the otherwise excellent textbook look bad.
Actually, you would be doing the author a favor by telling us the name and author of the book; that way, professionals could write to him/her about the error, so it could be fixed in subsequent editions.

RGV
 Mentor On the other hand, if the author is explaining how to solve y2 = x, for y, or solve y2 = 100 for y, then the answers are:y = ± √(x) = ±(x)1/2 for y2 = x y = ±10 for y2 = 100If this is the case you have only told us part of what the textbook was claiming, although the author may have also left a few details out of her/his explanation.

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