tg a=3, sin a < 0. вычислите: 3sin a + 2cos a

1)  tgn/6ctgn/3 + sqrt(2sin3n/4= sgrt3/3*sqrt3/3 + sqrt92*1/2) = 1/3 + 1 = 1ц 1/3
2)  = sin4 + sin4 = 2sin4
3)   = 2(cosa)^2 - (sina/cosa*cosa)^2 - (cosa/sina*sina)^2 =  2(cosa)^2 - (sina)^2  - (cosa)^2 = (cosa)^2 - (sina)^2