7sin^2 theta - 9 cos2 theta = 0

Question

Find the solutions for the equation 7sin^2 theta - 9 cos2 theta = 0 for 0 < or equal to theta < 360 degree. 

Answer 1

Use the double angle formula to replace cos 2θ by 1- 2sin²θ; you then have an equation that I believe you will able to solve.