This is a frequently asked question, to my surprise.
You have inserted the call to the integrator inside the function to be integrated. This starts an infinite recursion, because the integrator called the function to be integrated to get the values.
y = 1;
[t,y] = ode45(@odepro4, [0,2], y);
function dydt = odepro4(t,y)
dydt = (y.*t).^3 - (1.5*y);
This can be written to the M-file "myHomework.m".
Further explanations can be found, if you read the documentation: