Hooolas mis amores de colores , tengo una tarea me ayudan , - 3 sen x + cos ^ 2x = 3cos ^ 2x - 3 sen ^ 2x = 0?

Sea<img src="https://tex.z-dn.net/?f=a%3D%20%5Csin%20x" /> entonces

<img src="https://tex.z-dn.net/?f=-3a%2B%281-a%5E2%29%3D3%5C%5C%20%5C%5C%0Aa%5E2%2B3a%2B2%3D0%5C%5C%20%5C%5C%0A%28a%2B1%29%28a%2B2%29%3D0%5C%5C%20%5C%5C%0Aa%3D-1%5Cvee%20a%3D-2%5C%5C%20%5C%5C%0A%5Csin%20x%20%3D-1%5Cto%20%5Cboxed%7Bx%5Cin%5C%7B%5Cpi%20%2B%202k%5Cpi%5C%3B%2C%5C%3B%20k%20%5Cin%20%5Cmathbb%20Z%5C%7D%7D" />

Recuerda que<img src="https://tex.z-dn.net/?f=%5Ctext%7BRan%7D%20%28%5Csin%20%29%3D%5B-1%2C1%5D" />.