- #1

member 428835

I'm trying to put the first derivative of the modified Bessel function of the first kind evaluated at some point say ##\alpha## in a sum where the ##ith## function is part of the index. What I have so far is

Code:

```
n=3;
alpha = 2;
DBesselI[L_, x_] := D[BesselI[L, x], {x, 1}]
Sum[BesselI[L, alpha], {L, 1, n}]
```