Question

How do you find the value of the expression arccos (-0.7)?

Answer 1

`134^@43, 225^@57`

Explanation:

Use calculator:
cos x = - 0.7 --> arc `x = 134^@43`
Trig unit circle gives another arc x that has the same cos value:
`x = - 134^@43`, or `x = 360 - 134.43 = 225^@57` (co-terminal)