Some are more geared towards Symbolic Math (like Maple), some others are focused on numeric computations and even if they do symbolic math are severely limited.
You're right, Theano does symbolic differentiations, but this looks like it's in support of its main purpose (multi-dimensional problems)
TL;DR: If you want to calculate a triple integral symbolically go for Maple (or maybe SymPy), if you want to calculate its value go for NumPy or Theano
Some are more geared towards Symbolic Math (like Maple), some others are focused on numeric computations and even if they do symbolic math are severely limited.
You're right, Theano does symbolic differentiations, but this looks like it's in support of its main purpose (multi-dimensional problems)
TL;DR: If you want to calculate a triple integral symbolically go for Maple (or maybe SymPy), if you want to calculate its value go for NumPy or Theano