Question

What does `arcsin(cos ((-pi)/3))` equal?

Answer 1

`cos(-pi/3) = cos(pi/3)` because cosinus is even

watch your trigonometric circle you get

`cos(pi/3) = 1/2`
you search a number `x` such as

`arcsin(1/2) = x`

`1/2 = sin(x)`

watch your circle again you get

`x_1 = pi/6 + 2kpi` where `k in ZZ`

`x_2 = pi-pi/6 + 2kpi` where `k in ZZ`