Different results for integration

Different results for integration - Messages

#1 Posted: 6/7/2019 11:11:31 PM
mgklein

mgklein

0 likes in 10 posts.

Group: User

Hi.

I've been trying some silly problems in dynamics in Smath.

Came across an integration expression and tried to do it numerically.

Then, I tried with another "int" function and came out different results.

My questions is: should we always take on Maxima plugin's expression?


Another question, can we do symbolic diff() and returning the expression?

exm_12_2_din.sm (10 KiB) downloaded 28 time(s).
Thanks
#2 Posted: 6/8/2019 2:39:08 AM
Radovan Omorjan

Radovan Omorjan

325 likes in 2052 posts.

Group: Moderator

Hello,

There were mistakes in your file. You should pay attention to definite and indefinite integrals and the function arguments when using definite integrals. See the picture with corrections and hover the expressions in the file to see the difference.

definteg.PNG

exm_12_2_din-2corr.sm (12 KiB) downloaded 38 time(s).

Regards,
Radovan
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
#3 Posted: 6/8/2019 9:04:33 AM
Jean Giraud

Jean Giraud

983 likes in 6866 posts.

Group: User

Wrote

I've been trying some silly problems in dynamics in Smath.
Came across an integration expression and tried to do it numerically.
Then, I tried with another "int" function and came out different results.
My questions is: should we always take on Maxima plugin's expression?
Another question, can we do symbolic diff() and returning the expression?


Good idea to save Carlos adaptive integration.
Exceptional numerical integrator that meets Mathcad/Mathsoft Adaptive.
I have exhausted this integrator, it ranges from exact2atleast 6/8 decimals.
Hope it clarifies your questions ... Jean

Sanity.PNG

exm_12_2_din Sanity.sm (28 KiB) downloaded 39 time(s).
#4 Posted: 6/8/2019 4:24:59 PM
mgklein

mgklein

0 likes in 10 posts.

Group: User

Wrote

Hello,

There were mistakes in your file. You should pay attention to definite and indefinite integrals and the function arguments when using definite integrals. See the picture with corrections and hover the expressions in the file to see the difference.

Regards,
Radovan



I see what you did but with respect to "t" and "x". Just to be clear, the definite integral k(t) goes diffent because of the Constant? The constant C=0 and the expression is evaluated for t=4? I think I get it now.

Thanks, Rodovan.

Wrote

Good idea to save Carlos adaptive integration.
Exceptional numerical integrator that meets Mathcad/Mathsoft Adaptive.
I have exhausted this integrator, it ranges from exact2atleast 6/8 decimals.
Hope it clarifies your questions ... Jean



Sure it does.
I'll test this code.

Thanks, Jean.

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