Dear Bomber1,
Not all worksheet functions are available to Visual Basic. For a list of the ones that are, enter "list of worksheet functions available to visual basic" into the Answer Wizard in VB Help. A workaround is to enter the values and formulas into cells:
c1.Value = x
c2.Value = y
c3.Formula = "=Besselj(x,y)"
MyVar = c3.Value
Gregg
groberts1@austin.rr.com