Verify the identity: cos(-?)/1 + sin(-?) = sec? + tan? Solution cos(-x)=cosx and sin(-x)=-sinx So LHS=cosx/1-sinx =(cosx)(1+sinx)/(1-sinx)(1+sinx) =cosx(1+sinx)/(1-sin^2x) =cosx(1+sinx)/cos^2x =1+sinx/cosx RHS=secx+tanx=1/cosx+sinx/cosx =1+sinx/cosx So LHS=RHS Hence the identity is correct.