Question

How do you evaluate `csc^-1(2/sqrt3)` without a calculator?

Answer 1

`pi/3 + 2kpi`
`2pi/3 + 2kpi`

Explanation:

Use trig table of special arcs:
`csc x = 1/(cos x) = 2/sqrt3`
`sin x = sqrt3/2`
Trig table and unit circle give 2 solutions for arc x
`x = pi/3` and `x = pi - pi/3 = (2pi)/3`