Unless you can establish some relationship between the inputs, there may not be much more you can do than to reduce half of the trigonometric functions to sqrt functions.

Or if you can transform your inputs so that instead of working with Ma,Mb,Pa,Pb,

you're working with inputs that correspond to Ma*sin(Pa),Ma*cos(Pa),Mb*s

But that may depend on refactoring other parts of the algorithm that use this part.