I guess there is a limit bug here somewhere.  With MultiSeries things are OK...

L:=(x*BesselI(k-1, x)+x*BesselI(k+1, x))*BesselI(-k, x);
L := (x BesselI(k - 1, x) + x BesselI(k + 1, x)) BesselI(-k, x)
simplify(limit(L,x=0)) assuming k>0;
                               0
with(MultiSeries):
simplify(limit(L,x=0)) assuming k>0;
                          2 sin(Pi k)
                          -----------
                              Pi     

BesselLimit.mw

A problem with convert,StandardFunctions

Download hyp.mw

Saving a 3D object computed in Maple.  Maple itself has only limited capabilities for this.

There is a Maple library called JavaViewLib that sends the data from Maple to a Java applet called JavaView.

From there it can be viewed and saved in many different formats.

Find all the info at www.javaview.de

The last web page update was 2006, but the server that provides the free licenses is still running.

Mostly JavaViewLib...