Respuesta :

Answer:

For theta = 0 , π , 2π , 7π/6 and 11π/6

this equation holds !!

Step-by-step explanation:

[ Refer to the attached file ]

  • Used Formula :-

* Cos2x = 1 - 2sin²x

* Sinx is zero for x = nπ

* Sinx is negative in 3rd and 4th quadrant !!

Ver imagen smayra1191