Question

Using the unit circle, how do you find the value of the trigonometric function: cos(arctan(2))?

Answer 1

`1/sqrt5, -1/sqrt5`

Explanation:

In a Unit circle , the point representing the angle arctan2 would have coordinates `(1/sqrt5, 2/sqrt5)` in the first quadrant and
`(-1/sqrt5, -2/sqrt5)` in the third quadrant. Hence cos arctan2 would be `1/sqrt5, -1/sqrt5`