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

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

## Homework Statement

This is from a textbook:

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

## The Attempt at a Solution

100^1/2=10

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

Thanks.

## Answers and Replies

Homework Helper
hi solve! This is from a textbook:

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

## 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?)

solve

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.

Homework Helper
Dearly Missed

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

Staff Emeritus
Homework Helper
Gold Member

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 = 100​
If 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.