How to use integral() in a multi variable expression?

Hi! How could I writte a code to integrate the expression in relation to x(1) only?

a = @(x)x(1) + x(2)^2;

Answer 1

[Walter Roberson]

You would have to use the symbolic toolbox

   syms x1 x2
   int(a([x1,x2]), x1, LowerBound, UpperBound)

[Daniel Caliari]

Can't I use function handle?

[Walter Roberson]

That does use a function handle. It invokes the function handle a on the input [x1, x2], returning the symbolic expression x1 + x2^2 which is then integrated. If you need to turn the symbolic result back into a function handle then you can use matlabFunction .

If your question is whether you can use integral() to do an integral over one of the variables leaving the other undefined, then the answer is NO.

It is possible to do a 2D numeric integral using integral2(), such as

a = @(x)x(1) + x(2).^2;    %vectorize it!

fa = @(x,y) a([x,y])
integral2(fa, xlow, xhigh, ylow, yhigh)