Here is the textbook solution to a simple trigonometry problem I just completed. The Exercise was to rewrite the LHS in terms of $\cot\theta$.
$\sqrt{\frac{4}{\tan^6(\theta)}}=\frac{2}{\tan^3(\theta)}=2 \cdot \left( \frac{1}{\tan(\theta)}\right)^3 = 2 \cot^3(\theta)$
My answer was $\pm 2 \cot^3\theta$. My question is, when is it useful/necessary to write the $\pm$? Do you think I would be penalised for this in an exam?
Thank you!
I wasn't sure what to tag this, so I've tagged it algebra. Any other suggestions?