How to integrate a multivariate function in MatLab?

Question

How do I integrate something like (x + y) (or an expression with any number of variables) with respect to just one of the variables, let's say x from 0 to 1, and get a function of the other variable (1/2 + y in this case) back?

Answer 1

If you mean symbolically, then use:

syms x y
f=int(x+y,x,0,1)

which gives

f =
y + 1/2

then get f(y=4) from subs(f,4) which gives

ans =
9/2

If you have more than two variables, use:

syms x y z
f=int(x+y+z,x,0,1)

which gives

f =
y + z + 1/2

then for f(y=4,z=5) use subs(f,{y,z},[4,5]) gives

ans =
19/2