4sin^2x+7sin2x=4cos^2xСРОЧНО

Question

4sin^2x+7sin2x=4cos^2x
СРОЧНО

Answer 1

4sin^2x+7sin2x=4cos^2x

7sin2x=4cos^2x - 4sin^2x

7sin2x=4(cos^2x - sin^2x)

7sin2x=4cos2x       /соs (2x)

7 tg 2x= 4

tg 2x =4/7

2х=arctg(4/7) + Пn  n∈Z

x=(arctg4/7)/2 + Пn/2 , n∈Z