Matlab数值积分

问题描述

我正在尝试使用Matlab集成x，通过使用以下命令，该任务很简单:

I'm trying to integrate x using matlab, and that task is simple by using the following commands:

syms x

a=int(x)

问题是我不确定如何实现数值积分.我想使用不同的技术使用一定数量的间隔对x进行积分.

The problem is I'm not sure how to implement numerical integration. I want to integrate x using a set amount of intervals using different techniques.

有人可以帮助我进行数字积分的语法调用吗? MathWorks网站不是很有帮助.

Can anyone help me with the syntax call for numerical integration? The MathWorks site isn't very helpful.

我也确实知道有一种叫做陷阱的方法，但是我正在matlab中寻找其他方法，例如黎曼和近似.

I also do know there is a method called traps, but I'm looking for other methods within matlab, like Riemann sum approximation.

更新

因此，我要寻找的具体功能是将x分成8个区域，然后将这8个区域相加.除了trapz之外，还有其他预定义功能可以做到这一点吗?

So specifically what I'm looking for is a function that will break x into 8 pieces of area and then add those 8 pieces together. Is there a predefined function other than trapz that does such a thing?

好的，我想我得出的结论是，没有这样的事情.你必须自己做.

Okay, I think I've come to the conclusion that there is no such thing. You have to make your own.

推荐答案

对于数值积分，您可以使用大量函数:

For numerical integration you have a broad number of functions at your disposal:

trapz
quad
quadgk
integral

用于一维集成.

相反，如果您对多维集成技术感兴趣，则可以考虑使用以下功能

If, instead, you are interested in multi-dimensional integration techniques, you may think of making use of the following functions

dblquad
quad2d
integral2
integral3

编辑

在您的情况下，我将按照这种方式进行操作:

In your case, I would proceed this way:

x = 0:.1:2;
y = x;
trapz(x,y);

或

y = @(x) x;
quad(y,0,2);

编辑2

看一下:

clc,clear

s = 0:7;
y = @(x) x;

k = 1;
for ii = 1:numel(s)-1
  f(k) = quad(y,s(k), s(k+1));
  k = k + 1;
end
sum(f)

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