Question

3cos²x-2*5sin2x-2sin²x=0

Answer 1

3cos^2(x) - 5sin^2(x) - sin2x = 0 
3cos^2(x) - 5sin^2(x) -2sinxcosx = 0 
 5tg^2(x) + 2tgx - 3 = 0 
D = 64 
1) tgx = -1 x = - П/4 + Пn

2) tgx = 0,6 x = arctg0,6 + Пn