Some symbolic derivatives of certain special functions are not expanded automatically, but
FunctionExpand often helps to get a derivative-free closed form expression.
Derivative[1, 0][BesselJ][0, 1] (* Derivative[1, 0][BesselJ][0, 1] *) FunctionExpand[%] (* 1/2 π BesselY[0, x] *)
But for some functions, it takes too much time to evaluate. Possibly, there is even an infinite loop. For example, I left the following expression to evaluate overnight, and it was still running in the morning without any result or messages:
FunctionExpand[Derivative[1, 0][StruveL][0, 1]]
- Is there a workaround that could get an expanded form of the expression
Derivative[1, 0][StruveL][0, 1]in reasonable time?
- Is there an infinite-loop bug in the implementation of
FunctionExpandor do I just have to wait longer for the results (weeks, months, ...)?
- Is there any public information about what approaches are used by
FunctionExpandto expand derivatives?