Question

3cos(3π/2+x)-5cosx=0​

Answer 1

Используя формулы приведения cos(3π/2 + x) = sin x

3sin x - 5cos x = 0

3sin x = 5cos x |:cos x ≠ 0

3tg x = 5

tg x = 5/3

x = arctg(5/3) + πn, n ∈ Z