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kcotton1-Visitor
1-Visitor
November 15, 2015
Question

Integral Function Issue

  • November 15, 2015
  • 3 replies
  • 2587 views

Hello,

I'm trying to use the integral function of MathCAD, which I haven't used before, and getting  "This calculation doesn't converge to a solution".  I think it has something to do with using a ray with the specific values for integration. I included the graph of what I'm trying to integrate. Any help would be great.

Thanks,

Kendall

3 replies

R
RichardJ19-Tanzanite
19-Tanzanite
November 15, 2015

If you want to use the integrals in Mathcad you have to integrate a function. The best way to turn your data into a function is usually spline interpolation, but for your data rational function interpolation may well be better. To integrate data directly you would have to use the trapezoidal rule or Simpson's rule. See "Help", "Data analysis extension pack", "Application examples", "Numerical integration of data" for details of either approach.

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-MFra-21-Topaz II
21-Topaz II
January 26, 2016

My attempt to resolve the issue. See the attached worksheet.

F
Fred_Kohlhepp23-Emerald I
23-Emerald I
January 26, 2016

You have "solved" the problem by (luckily) finding symbolic functions for each of your integrals, congratulations.

So Mathcad was able to evaluate the integral at each point there was data.

But your first heuristic solution integral is the integral of a constant between two points:

Now, if that's what you want great, but if you want to integrate that curved function, this isn't it.

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-MFra-21-Topaz II
21-Topaz II
January 27, 2016

... It is clear what you say. And what about the second heuristic solution?

second heuristic.jpg

F
Fred_Kohlhepp23-Emerald I
23-Emerald I
January 28, 2016

Getting closer!

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