How do you evaluate arcsin(cos(pi/3))?

Answer is ##pi/6##
##sin^(-1)(cos(pi/3))=sin^-1(1/2)## (since ##cos60^@=1/2)##
##sin^(-1)(cos(pi/3))=sin^-1(sin(pi/6))##[since from angle table]
##sin^(-1)(cos(pi/3))=cancelsin^-1(cancel(sin)(pi/6))##
##arcsin(cos(pi/3))=pi/6##