Passing integral to another integral

By no means am I a MATLAB expert. I'm trying to pass an integral to another integral, in an instance where there's no obvious way to write this as higher-dimensional integral. For instance, suppose I need to integrate the square of a finite integral:

f = @(x) sin(x).^2
g = @(x) integral(@(z)f(z),0,x)
h = @(x) integral(@(z)g(z).^2,0,x)

The problem I run into is that, to compute h, the limits of g are not scalars. The error message is: "A and B must be floating-point scalars."

Answer 1

[Gautham Sholingar]

A possible approach for this scenario is to use the functions available in the Symbolic toolbox to declare variables x,y,z and three functions which you can call with the specific integral limits. For example:

syms x y z % declare symbols
F = sin(x).^2;
G = int(F,x,0,y);
H = int(G^2,y,0,z);
subs(H,z,2)

The following documentation links explain these function in detail:

https://www.mathworks.com/help/symbolic/subs.html

https://www.mathworks.com/help/symbolic/int.html