Question

How do you calculate `sin^-1 (-0.4)`?

Answer 1

`x = 203^@58`
`x = - 23^@58`, or `x = 336^@42` (co-terminal)

Explanation:

`sin^-1 (-0.4)` --> arc x whose sin is (-0.4)
sin x = - 0.4. Calculator gives -->
x = - 23^@58, or x = 336^@42 (co-terminal)
Unit circle gives another x that has the same sin value (- 0.4)
`x = 180 - (- 23.58) = 180 + 23.58 = 203^@58`