Which is right (and why)?
or
Actually, according to my calculator, the first one is right, so I really only want to know why.
Isn't ? If so, then and the second one is "also" right.
Note that my calc says:
, and
Is the conclusion that is only true for ?
Thanks
You are right, that rule is not always true.
Here is a wiki article part about it:
Square root - Wikipedia, the free encyclopedia