# How do you evaluate #cos^-1 0.8217#?

##### 2 Answers

Jul 15, 2018

#### Explanation:

One can compute

Jul 15, 2018

#### Explanation:

The question can be read as ..

"What angle has a cos value of

If you just need an angle in a right-angled triangle, then on a scientific calculator you would key in:

shift/alt/

However, if you want to include angles from

Cos is positive in the first

The angle in the

The angle in the