Evaluate please:

Question

a.) arcsin(sin 13pi/16)
b.) arccos(cos[-pi/18])
c.) arcsin(sin pi/18
d.) arcsec(-√2)
e.) arctan(-√3/3)

Answer 1

a) isn't arcsin(sin(?)) the inverse of itself?
so 13π/16

b) and c) same thing, except by definition arcsin( ..) will give you the smallest positive angle

so arccos(cos(-π/18) = π/18

d) arcsec(-√2)
the angle Ø so that secØ = -√2
or cosØ = (-1/√2)
Ø = 135° or 3π/4

e) -π/6