Question

sinα если cosα=-3/5 π<α<3π/2 №1


sin(90°-α)-cos(180°-α)+tg(180°+α)-cos(270°-α) №2

сtg13°×ctg17°×ctg21°......ctg77° №3

Answer 1

1. -0,8
2. 0,4
3. .....