What is the arcsine of 1 ?
arcsin 1 = ?
The arcsine is the inverse sine function.
Since
sin π/2 = sin 90º = 1
The arcsine of 1 is equal to the inverse sine function of 1, which is equal to π/2 radians or 90 degrees:
arcsin 1 = sin-1 1 = π/2 rad = 90º