Question 1015674
.
Find the exact value of cos^-1 the quantity square root of two divided by two.
-------------------------------------------------------------------------


You need to find {{{arccos(sqrt(2)/2)}}}.


Let {{{alpha}}} be that angle: {{{cos(alpha)}}} = {{{sqrt(2)/2}}}.


Ask yourself: what angle is this?


Surely, {{{alpha}}} = {{{pi/4}}} = 45 degrees.


<U>Answer</U>. {{{arccos(sqrt(2)/2)}}} = {{{pi/4}}} = 45 degrees.