How do you calculate the ##arcsin (-1/ sqrt 2)##?

Calculate ##arcsin (-1/sqrt2)##

Ans: ##(5pi)/4 and (7pi)/4##

Unit circle and trig table of special arcs --> ##sin x = - 1/sqrt2 = - sqrt2/2## --> ##arc x = - pi/4 ## Unit circle gives another arc x that has the same sine value: ##x = pi + pi/4 = 5pi/4.## Ans: ##x = (5pi)/4##, and ##x = (7pi)/4## (or -pi/4)