How do I plot a univariate integral?

Question

Tatte Berklee 2020-8-4

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/574723-how-do-i-plot-a-univariate-integral

回答： Alan Stevens 2020-8-7

I am the following code, and I am trying to PLOT below integral over some positive real numbers's range x:

[p,S] = polyfit(x, y, 6);
fun = @(x) x/(p(1,1)*x.^6+p(1,2)*x.^5+p(1,3)*x.^4+p(1,4)*x.^3+p(1,5)*x.^2+p(1,6)*x+p(1,7)).^2;
exp = integral(fun,0,Inf,'ArrayValued',true);

Is there away I can plot the function, FUN, and with the integration?

I looked at cumtrapz, but I don't understand how it would work with a univariate integral case?

Can someone help?!

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

Alan Stevens 2020-8-7

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/574723-how-do-i-plot-a-univariate-integral#answer_476608

在 MATLAB Online 中打开

Like this (you will need to replace my arbitrary polynomial with your own):

% Arbitrary polynomial
p = [2 1 -1 3 1 -1 5];
fun = @(x) x./(p(1,1)*x.^6+p(1,2)*x.^5+p(1,3)*x.^4+p(1,4)*x.^3+p(1,5)*x.^2+p(1,6)*x+p(1,7)).^2;
x = 0:0.01:2;
y = fun(x);
yint = zeros(size(x));
for i = 1:length(x)
yint(i) = integral(fun,0,x(i),'ArrayValued',true);
end
plot(x,y,x,yint)
xlabel('x'),ylabel('y')
legend('function','integral')