LHS=(tanx/(1+cosx)) + (sinx/(1-cosx))
=(tanx(1-cosx) + sinx(1+cosx))/(1-cos^2x)
=(tanx-tanxcosx + sinx+sinxcosx)/sin^2x
=(sinx/cosx-sinx/cosx*cosx + sinx+sinxcosx)/sin^2x
=(sinxsecx-cancelsinx +cancel sinx+sinxcosx)/sin^2x
=(sinxsecx)/sin^2x +(sinxcosx)/sin^2x
=secx/sinx +cosx/sinx
=cotx + secxcscx=RHS