How can I use feval, linespace and int()?

I want to calculate an indefinite integral and then draw it. A prerequisite is that the interval and the number of points are specified.

It works great:

function test
    s = @(x) sin(1./x);
    numPoints = 20;
    xvec = linspace(0.01,0.1,numPoints);
    yvec = feval(s,xvec);
    plot(xvec,yvec)
end

How to do the same with the int() ?

I have tried different examples here is one of them:

function test
    syms x; 
    ex = int(x.^2); 
    s = @(ex) ex;
    numPoints = 20;
    xvec = linspace(1,10,numPoints);
    yvec = feval(s,xvec);
    plot(xvec,yvec)
end

How can I use feval, linespace and int()?

[Riccardo Scorretti]

The line s = @(ex) ex; is wrong, because you are "shading" the function ex. Basically it is the same as:

s = @(x) x;

Answer 1

[Riccardo Scorretti]

You can do like that:

syms x; 
ex = int(x^2); 
s = @(x) subs(ex, 'x', x);
numPoints = 200;
xvec = linspace(1,10,numPoints);
yvec = feval(s,xvec);
plot(xvec,yvec)

That's being said, in my opinion this is better:

syms x; 
ex = int(x^2); 
fplot(ex, [1 10]);

[Vsevolod Kolobov]

Thank you very much!