How to use the inverse function of cosine?

you are very welcome

the most important thing to remember is that you use inverse trig when you want to find an angle!

$$\\If cos \theta = 0.34\\
then\\
\theta = inverse\; cos\; of\; 0.34\\
$Inverse cos of 0.34 is often written as $cos^{-1}(0.34)\\
$Arc cos is exactly the same as inverse cos so on the web2.0calc this can be entered as $
[2nd][acos](0.34)=$$

I am just typing into the input box so i dont need the [2nd] I will enter     acos(0.34)=

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{cos}}^{\!\!\mathtt{-1}}{\left({\mathtt{0.34}}\right)} = {\mathtt{70.123\: \!125\: \!929\: \!921^{\circ}}}$$

Thank you so much !