# Product of one-dimensional integrals, numerical integration

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DIMITRIS GEORGIADIS on 17 Apr 2021
I want to compute the following product of integrals numerically using the and the tool of Matlab:
where, are known scalar values gathered into a vector and f, g are two continuous and differentiable functions. Any ideas?
Matt J on 17 Apr 2021
Edited: Matt J on 17 Apr 2021
What ideas do you need? You have already said that integral() is the tool you are going to use. That does seem very appropriate.
DIMITRIS GEORGIADIS on 17 Apr 2021
Thank you for your answer. I mean how to program it appropriately.

Divija Aleti on 22 Apr 2021
Hi Dimitris,
Have a look at the following example code. I have assumed different functions for 'f' and 'g' and integrated their product from a lower bound of -2 to an upper bound of 2 using the 'int' function. There are 5 known scalar values here (n = 5), which I have gathered into a vector yi.
yi = 1:5;
syms x y
g(x,y) = x*y;
h = 1;
for i = 1:5
f(y) = yi(i)*y^3;
hi = int((f(y).*g(x,y)),y,-2,2);
h = hi.*h;
end
Hope this helps!
Regards,
Divija
DIMITRIS GEORGIADIS on 22 Apr 2021
Thank you Divija!