Arcsine of a value like y is the inverse of that value y.
Lets take that,
arcsin (-√3/2) = Ф then,
sin Ф = -√3/2
For a right triangle with length 1 and base √3, has a hypotenuse of 2.
This gives us,
sin 30° = √3/2
∴ sin -30° = -√3/2
This now means that arcsin (-√3/2) = -30.
But since we measure angles in anticlockwise direction, -30° = 330° and 210°.
Answer: arcsin (-√3/2) = 210° and 330° for angles below 360°.
