5.42. Oblicz, b) tg 120^ * ctg 30^ +cos^ 2 135^ c) (cos 120^ -tg150^ )^ 2 d) ( (sin 135^ -tg120^ )*(cos 135^ -ctg150^ ) .

5.42. Oblicz, b) tg 120^ * ctg 30^ +cos^ 2 135^ c) (cos 120^ -tg150^ )^ 2 d) ( (sin 135^ -tg120^ )*(cos 135^ -ctg150^ ) .