%% Using an external function
% Assuming you defined the function f, or it is a built in function
% call a function f and evaluate f(2).

x = 2;
f(x)

%% Using an inline function
% Define a function g and evaluate g(3).

g = inline('x^2+2*x+2');
g(3)

%% Using a symbolic function
% Define a symbolic function h and evaluate h(4).

x = 4;
h = 'x^3+3*x-5';
eval(h)

%% Using a function handle
% Define a function i to be f and evaluate i(5) and i(6).

i = @f;
i(5)

feval(i,6)

%% Error messages
% The function j was defined, j(x) = x unless x = 0 in which case it stops
% with an error message.

j(1)

j(0)

j(3)