how can we check convex or nonconvex feasible?

example if i have 20 constraints functions.These functions cut the objective function and create the feasible region. Their intersections can become edges and create a nonconvex feasible region even though all of them are convex.Is there any way to check it in MATLAB.Can i plot all these functions and check it ? but the problem is there are multi-variables. thank you for all your answers!

best regards!

[Torsten]

The intersection of convex regions is always convex.

Thus if all your constraint regions are convex, so is their intersection.

Best wishes

Torsten.