Notice you have:
fun= @(x, y) x.*exp(-y.*x);
which is a function of two variables. But you try
c= @(y)integral(@(x) fun, 0,1);
which does not pass any parameters to the function. You probably intended
c= @(y)integral(@(x) fun(x), 0,1);
But notice that you are not passing y, so you would need
c= @(y) integral(@(x) fun(x, y), 0,1);
Then you have
fun1= @(y) 1/2-(1/pi).*y.*c;
c1 = integral(fun1, 0,1);
this attempts to invoke c, but c is a function handle. You have to pass a value to the handle:
fun1 = @(y) 1/2-(1/pi).*y.*c(y);
c1 = integral(fun1, 0,1);
I think that should work.
