If I assume that the variables are positive number, should I put absolute value when taking them of out of a square root?

Question

If I assume that the variables are positive number, should I put absolute value when taking them of out of a square root?

like if I assumed that u is a positive number and I have square root u to the power 2. Should it be |u| or u?

Answer 1

If you assume that $u$ is positive, then $|u|=u$, so you can write either $u$ or $|u|$ and nothing should change.