Difficult implicit function in mathematica.

In summary, the conversation is about solving an implicit function numerically in Mathematica. The function involves integrals and unknown variables, with the goal of simplifying it by assuming constants for certain variables. The speaker is seeking help from someone who is familiar with Mathematica to guide them through the process.
  • #1
Warri
1
0
Hi everybody. I have an impicit function that I want to solve numerically in mathematica it looks like:

Code:
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:
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  • #2
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:

Related to Difficult implicit function in mathematica.

1. What is an implicit function in mathematics?

An implicit function is a mathematical function where the dependent variable cannot be easily isolated, and therefore cannot be expressed explicitly in terms of the independent variable. This means that the relationship between the variables is defined by an equation rather than a formula.

2. How can I solve a difficult implicit function in Mathematica?

There are several methods for solving implicit functions in Mathematica, such as using the built-in function Reduce or using the NSolve function with appropriate constraints. It is also helpful to use the ContourPlot function to visualize the implicit function and get an idea of the solution.

3. Can implicit functions have multiple solutions?

Yes, it is possible for an implicit function to have multiple solutions. This can be visualized by using the ContourPlot function in Mathematica, where each solution will appear as a separate curve on the graph.

4. What is the difference between an implicit function and an explicit function?

The main difference between an implicit and explicit function is how the dependent variable is expressed. In an explicit function, the dependent variable is directly expressed in terms of the independent variable, while in an implicit function, the dependent variable is defined by an equation involving both the independent and dependent variables.

5. Can implicit functions be differentiated in Mathematica?

Yes, it is possible to differentiate implicit functions in Mathematica using the D function. However, since implicit functions cannot be expressed explicitly, the result of the differentiation will also be in implicit form.

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