# Difficult implicit function in mathematica.

1. Sep 15, 2010

### Warri

Hi everybody. I have an impicit function that I want to solve numerically in mathematica it looks like:

Code (Text):
f[x] == b1 \!$$\*SubsuperscriptBox[\(\[Integral]$$, $$0$$, $$L$$]$$c[ x, \[Alpha]] f[\[Alpha]] SuperscriptBox[\(E$$, $$-\( \*SubsuperscriptBox[\(\[Integral]$$, $$0$$, $$\[Alpha]$$]f[\[Eta]] \
\[DifferentialD]\[Eta]\)\)] \[DifferentialD]\[Alpha]\)\) + b2 \!$$\*SubsuperscriptBox[\(\[Integral]$$, $$0$$, $$L$$]$$c[ x, \[Alpha]] \[Rho][\[Alpha]] \( \*SubsuperscriptBox[\(\[Integral]$$, $$0$$, $$\[Alpha]$$]f[\[Xi]]
SuperscriptBox[$$E$$, $$\(-\( \*SubsuperscriptBox[\(\[Integral]$$, $$0$$, $$\[Xi]$$]f[\[Eta]] \
\[DifferentialD]\[Eta]\)\) -
\*SubsuperscriptBox[$$\[Integral]$$, $$\[Xi]$$, $$\[Alpha]$$]\[Rho][\
\[Eta]] \[DifferentialD]\[Eta]\)] \[DifferentialD]\[Xi] \
\[DifferentialD]\[Alpha]\)\)\)
(It's my first time doing something like this so if the code does not work, please say so)

When I put it in mathematica f will be the only unknown. For simplicity it can be assumed at first that c is constant (This one is already solvable for me, next it will probably be a step function, not continuous) and rho is constant (it will be some smooth function)

This is for me a rather hard cookie to crack. I hope there is someone who reads this who can tell me how to do this. Sorry I don't have all the functions yet.

Edit: I use mathematica version 7.0.1.0

Last edited: Sep 15, 2010
2. Sep 15, 2010

### jackmell

Block-it, Cell/Convert To/Raw Input form.

That above is what you have to do to cut-and-paste Mathematica-formatted code into a post here without all the unnecessary formatting codes that this forum can't interpret anyway. Granted, you loose all the nicely-formatted math forms and sometimes it's still hard to read, but the reader, if they wished, can invert that by cutting the text out of this forum, pasting it into a Mathematica notebook, then:

Block-it/Cell/Convert To/Standard Form

And that gives an easier read.

Last edited: Sep 15, 2010