This little integral has been holding me up for weeks. Has anyone come across a similar integral in their work.
$\int {\frac{d x}{cI_0(x)}} $
This little integral has been holding me up for weeks. Has anyone come across a similar integral in their work. $\int {\frac{d x}{cI_0(x)}} $ 


I doubt that there is a closedform formula. Neither Maple nor Mathematica could find one. They don't even get formulas for the case $c=0$. Would a series expansion in $x$ be of any use? It is $$ \frac{1}{c1} x + \frac{1}{12 (c1)^2} x^{3} + \frac{c+3}{320 (c1)^3} x^{5} + $$ $$ + \frac{c^2+16 c+19}{16128 (c1)^4} x^{7} + \frac{c^3+65 c^2+299 c+211}{1327104 (c1)^5} x^{9} + $$ $$ + \frac{c^4+246 c^3+3156 c^2+7346 c+3651}{162201600 (c1)^6} x^{11} + O(x^{13})$$ 

