Question

Решите уравнение : 3sin^2x-3sinxcosx-4cos^2x=-2

Answer 1

3sin²x -3sinx*cosx -4cos²x =-2(sin²x +cos²x) ;
5sin²x -3sinx*cosx -2cos²x =0 ;
5tq²x -3tqx -2 =0 ;
[tqx = -2/5 ; tqx =1 ;
[ x = -arctq2/5+πk ;x =π/4+πk ,k ∈Z .