1. Найти sin α и cos α, если tg α/2 = 5. 2. Найти sin 2α и cos 2α, если
a) tg α = — 3; б) ctg α = 3.
3 Доказать, что sin 2α и tg α имеют один и тот же знак {оба отрицательны, оба положительны или оба равны нулю) при любом α.
5. Известно, что tg α/2 = 1/2. Найти:
а) sin4 α — cos4 α;
б) sin α • cos α • cos 2α.
2
usually (1)sleeps eight hours and doesn’t
go to bed late .
He does morning(2) exercises regularly
and runs 10 km every day.
Alex (3) doesn't like watching TV or playing
computer games. He thinks it’s (4) better
to ride a bike or walk in the park .
Last year my brother (5) kept to a very
strict diet of vegetables, water and fish before an important match.
I hope Alex (6) make a very
successful career in football because he is a real sportsman.
sleep