Найдите 3cosx,если sinx=-2корень2/3 и 270°

cosx = 1 - sin^2x sinx = -2√(2/3) 3cosx = 3 - 3*(-2√(2/3) = 3 - 6√(2/3) 2)  sinx = 270 cosx = 1 - (sin^2)[270] = 1 - (√3/2)^2 = 1 - 3/2 = - 1/2