when doing an inverted cosine how should i set it up on the calculator for the most accurate answer?
Not sure what you mean but
$$\\cos\theta=0.63\\ \theta = $inverse cos $ 0.63\\ \theta=cos^{-1}0.63\\\\ $ this is the same as $\\\\ \theta=arc cos 0.63\\ \theta=acos 0.63\\$$
Just use 2nd function acos
