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integration help function 1/x(e^x -1) from 10^-19 ish to infinity

Asked by Sofia Wood on 8 Sep 2019
Latest activity Commented on by Rik
on 8 Sep 2019
I want to integrate 1/x(exp(x) -1) from a very small number of order 10^(-19) to infinity. The integral function refuses to do this. Any help?

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1 Answer

Answer by Jackson Burns on 8 Sep 2019

Hi Sofia!
Since you didn't post any code or errors, I don't know what was wrong. It was likely an error with your function definition. Functions that are going to be called with matrices need to be able to operate on matrices, so instead of using / we would use ./ which is elementwise division (otherwise we would be attempting matrix divison, which is not defined).
Here's my solution:
f = @(x) (exp(x) - 1)./x
sol = integral(f,1*10^-19,Inf)
I can't tell exactly what function you are trying to integrate, so I apologize if it is the incorrect one.
Good luck!

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I suspect it should be f=@(x)1./(x.*(exp(x) -1)); instead, but your point still stands.

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