fun stuff...First let ((1+cosx)/(1-cosx)) = uf(x) = ln(u)f'(x) = (1/u)(du/dx) = (1-cosx)/(1+cosx) * (d((1+cosx)/(1-cosx))/dx)=(1-cosx)/(1+cosx)*((1-cosx)d(1+cosx) - (1+cosx)d(1-cosx))/((1+cosx)(1-cosx...