Question

How do you find the value for `cos^(-1) [(cos(135')]`?

Answer 1

`cos^(-1)[cos(135')] = 135'`

Explanation:

`cos^(-1)(x)` or `arccos(x)` is the angle, `theta` for which `cos(theta) = x`.

If `x = cos(135')` then `theta = 135'`

(It is unusual to have specified the angle in minutes; if it is relevant, note: `135' = 2^o15'`)