#LHS=sintheta/(1-costheta)+(1-costheta)/sintheta#
#=(sintheta*sintheta)/((1-costheta)sintheta)+(1-costheta)/sintheta#
#=sin^2theta/((1-costheta)sintheta)+(1-costheta)/sintheta#
#=(1-cos^2theta)/((1-costheta)sintheta)+(1-costheta)/sintheta#
#=((1-costheta)(1+costheta))/((1-costheta)sintheta)+(1-costheta)/sintheta#
#=(1+costheta)/sintheta+(1-costheta)/sintheta#
#=(1+costheta+1-costheta)/sintheta#
#=2/sintheta=2csctheta=RHS#
Verified