'... a special type of function in MATLAB called a "function function".'
There is nothing special about a function that accepts a function handle as an input.
'How do you make a function that accepts another arbitrary function as an input argument?'
A function handle is a fundamental MATLAB data type, so they can be passed just like any other data type. Simply define your function with an input argument, and inside that function you can call that input argument as a function. For example:
function myfun(infun)
x = 0:0.1:pi;
y = infun(x);
plot(x,y)
end
and then call it with a function handle:
myfun(@sin)
A function handle is just like any other variable, you can pass it, allocated it to another variable, etc.:
f = @sin
g = f;
g(pi)
