Question

2cos^2x+7sinx+2=0 решите плиз

Answer 1

2(1-sin^2 x)+7sinx+2=0
2-2sin^2 x +7sinx +2=0
2sin^2 x- 7sinx-4=0
Замена
2у^2-7y-4=0
y=-1/2, y=4-не прин
x=-π/6+2πk,k∈z
x=-5π/6+2πk,k∈z