#2sin^2theta=1# #sin^2 theta=1/2# #sintheta=sqrt (1/2) or sintheta=-sqrt(1/2)# #sintheta=sqrt2/2 or sintheta=-sqrt2/2# #theta=pi/4+2kpi or theta=pi-pi/4+2kpi or theta=-pi/4+2kpi or theta=-(pi-pi/4)+2kpi, k in mathbbZ# #theta=pi/4+kpi or theta=-pi/4+kpi, k in mathbbZ# #theta=pi/4+kpi/2, k in mathbbZ#
or written a bit differently #theta=((2k+1))/4pi , k in mathbbZ#