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Sep 22, 2021
06:51 PM

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Sep 22, 2021
06:51 PM

Integral Function Fails to Solve

FOR A REASON OR ANOTHER THE SOLVER DOESN'T PERFORM THE INTEGRATION.

The program is typically solving for Int [a to b] (Ax+B)^(-3) dx.

--------However, I have several Matrices defined.-------

Initially the first matrix in the Integrand function resulted in errror : <Not a Singular Matrix.>

Thus recognizing the matrix as x, I redefined x as xn, and dxn. Please see Theta2 equation.

I know the solution, I wish for the program to simplify future problems.

Solved! Go to Solution.

Labels:

1 ACCEPTED SOLUTION

Accepted Solutions

Sep 22, 2021
08:02 PM

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Sep 22, 2021
08:02 PM

5 REPLIES 5

Sep 22, 2021
07:51 PM

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Sep 22, 2021
07:51 PM

Not sure if thats what you'd like to achieve, but why do you use symbolic evaluations? You quickly get the numeric result by using the normal numeric evaluation (=)

In case of theta1 you did not defined E and so you see E in the symbolic result. If this was a mistake, then define E and again use numeric eval. If it was no mistake you could make theta1 a function of E and (numerically) evaluate at various values for E if thats what you are after.

BTW, I guess the reason why the symbolics fails are the units of the integral limits. The symbolics doesn't know anything about units!

Sep 22, 2021
09:11 PM

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Sep 22, 2021
09:11 PM

No Sabía :: I didn't know

@Werner_E wrote:

Not sure if thats what you'd like to achieve, but why do you use symbolic evaluations? You quickly get the numeric result by using the normal numeric evaluation (=)

In case of theta1 you did not defined E and so you see E in the symbolic result. If this was a mistake, then define E and again use numeric eval. If it was no mistake you could make theta1 a function of E and (numerically) evaluate at various values for E if thats what you are after.

BTW, I guess the reason why the symbolics fails are the units of the integral limits. The symbolics doesn't know anything about units!

"The symbolics doesn't know anything about units!"

Sep 22, 2021
08:02 PM

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Sep 22, 2021
08:02 PM

Prime7

Without units "m" and x2:=x[2 and x3:=x[3

Sep 23, 2021
05:17 AM

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Sep 23, 2021
05:17 AM

Plotting the result, check the equation what you want.

Sep 23, 2021
05:40 AM

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Sep 23, 2021
05:40 AM

My two cents.

This will help if:

- you want to know how the result of this integral depends on the parameter values of the function, or

- you need the result of this integral for many sets of parameter values.

- you need the result of the integral to be maximally accurate (Note that numerical integration results in an approximation).

It will NOT help if the integral has no symbolic solution.

But if you are only interested in numerical result of a single evaluation, you may be better off not using symbolics.

Success!

Luc