R(\sin x,\cos x) = \frac{{1 + 2\cos x}}{{\sin x(3 - \cos x)}} \\ 

 R( - \sin x,\cos x) = \frac{{1 + 2\cos x}}{{ - \sin x(3 - \cos x)}} =  - \frac{{1 + 2\cos x}}{{\sin x(3 - \cos x)}} =  - R(\sin x,\cos x) \\