Solve y''+ytanx+ycos^2x =0 given that z=sinx by the method of changing the independent variable

Solve y''+ytanx+ycos^2x =0 given that z=sinx by the method of changing the independent variable
Solve y''+ytanx+ycos^2x =0 given that z=sinx by the method of changing the independent variable
Solve y''+ytanx+ycos^2x =0 given that z=sinx by the method of changing the independent variable

variable