numerical integration __ integral limits being variables
4 visualizaciones (últimos 30 días)
Mostrar comentarios más antiguos
Meva
el 5 de Abr. de 2015
Hello, I want to numerically integrate functions whose upper limits x, lower limits 0. Say;
int_0^x f(x) dx
Which method should I use. trapz, simpson, or omething else and which command ?
I mean can you send a simple example of doing this please? Thanks
0 comentarios
Respuesta aceptada
Roger Stafford
el 5 de Abr. de 2015
There are a number of ways you can proceed. One way is to use 'int' with a variable upper limit. See:
http://www.mathworks.com/help/symbolic/int.html
If that does not succeed (which often happens) you can do numerical integration using the 'cumtrapz' function which also allows you to have a variable, though discrete, upper limit. See
http://www.mathworks.com/help/matlab/ref/cumtrapz.html
Finally, there are several functions in the File Exchange which are numerical but have higher precision. I wrote one of these. It is located at:
http://www.mathworks.com/matlabcentral/fileexchange/19152-cumulative-cubic-integration
0 comentarios
Más respuestas (1)
Star Strider
el 5 de Abr. de 2015
If you are numerically integrating functions, use integral (or quad and its friends if you don’t have integral). You will obviously have to define what value ‘x’ is to do a numerical integration.
If you want to do a symbolic integration (and your function is integrable), use the Symbolic Math Toolbox int function.
3 comentarios
Star Strider
el 5 de Abr. de 2015
You can use cumtrapz with data returned by your function, but not with your function itself. If you want to use a function, you have to use integral or quad, as I wrote before.
Ver también
Categorías
Más información sobre Numerical Integration and Differentiation en Help Center y File Exchange.
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!