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)