Question #18ea9

1 Answer
Dec 12, 2016

RHS=1+(2cosx(1+cosx))/sin^2xRHS=1+2cosx(1+cosx)sin2x

=1+(2cosx(1+cosx))/(1-cos^2x)=1+2cosx(1+cosx)1cos2x

=1+(2cosx(1+cosx))/((1-cosx)(1+cosx))=1+2cosx(1+cosx)(1cosx)(1+cosx)

=1+(2cosxcancel((1+cosx)))/((1-cosx)cancel((1+cosx)))

=1+(2cosx)/(1-cosx)

=(1-cosx+2cosx)/(1-cosx)

=(1+cosx)/(1-cosx)=LHS

Proved