Найдите значение выражения если tg =2 , 50 sin²a+sina 2-sin²a ; cos²a+3cosa sina 3+cos²a .

1)
s = sin(a)
c = cos(a)
t = tg(a) = 2

s/c = t = 2
=>
s = 2c

tt + 1 = 1/(cc)
=>
cc = 1/(tt + 1) = 1/5

(4cc + 2c)/(cc + 3c) = (0.8 + 2c)/(0.2 + 3c) = (0.8 + 2/√5)/(0.2 + 3/√5) = (0.8√5 + 2)/(0.2√5 + 3)

ответ:



2) sina 3 - это синус альфа в кубе? sss?

ss + cc = 1
=>
ss = 1 - cc
=>
2 - ss = 2 - 1 + cc = 1 + cc = 1 + 1/5

sss = 2c * (1 - cc) = 2/√5 * (1 - 1/5) = 2/√5 - 2/(5√5)

ответ: (1 + 1/5)/(2/√5 - 2/(5√5)).