The same answer I gave in the other thread you posted in:
Trigonometric functions are neither convex nor concave,. They can only be “convexified” by means of an approximation, such as a suitable Taylor series. The one term Taylor series approximation for sin(x) is x, and the two term Taylor series approximation is x - x^3/6, is convex for x < 0 and concave for x > 0, hence neither convex nor concave…Any higher order Taylor series approximation for sin(x) will be neither convex nor concave. cos(x) does allow the Taylor series approximation 1-x^2/2, which is concave, and may or may not be adequate for purposes of optimization.
I recommend you use a non-convex nonlinear solver, which you can not do via CVX. You can consider using YALMIP…