I just want to know the reason why the integral function doesn't work this way?

Question

Harsha vardhan naidu 2020-4-15

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/518099-i-just-want-to-know-the-reason-why-the-integral-function-doesn-t-work-this-way

评论： Steven Lord 2020-4-15

%p is a function handle so what's the problem.

Now i am working on finding response of the rectangular plate. So, after solving I get a function as an output and I gotta integrate that function between a certain interval to find a constant. So let us assume f is the function i got as an output. If i give f as an input to integral function I am geting an error saying "FUNCTION PASSED TO INTEGRAL FUNCTION MUST BE A FUNCTION HANDLE" so i created another variable p and made it a function handle now i am getting an error saying "INPUT FUNCTION MUST RETURN SINGLE OR DOUBLE VALUES. FOUND SYM". Looking for someone's help. Any way to solve this issue?

syms x;

f= x^2;

p = @(x) f;

q = integral(p,0,1)

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Bjorn Gustavsson 2020-4-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/518099-i-just-want-to-know-the-reason-why-the-integral-function-doesn-t-work-this-way#answer_426211

在 MATLAB Online 中打开

You have to convert the symbolic function to a function-handle that returns a scalar double. You can do this for your example problem:

F = matlabFunction(f);
q = integral(F,0,1);

The first step converts the symbolic expression into a matlab-function-handle.

HTH

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Steven Lord 2020-4-15

在 MATLAB Online 中打开

Another alternative, if you want to perform the integration symbolically, would be to call the int function instead of integral. The signature is slightly different (you need to specify the variable over which you're integrating) but they're still quite similar.