Undefined function 'diff' for input arguments of type 'function_handle'.

I am trying to produce a function that receives an inital input x0 (for example, x0 = 1) and the result should be the function e^2sin(x) - x at x0 and it's derivative's function at x0. I keep getting the error "Undefined function 'diff' for input arguments of type 'function_handle'." and I'm not sure why. Any advice would be appreciated!

function [Val1, Val2] = nonlinear1(x0)
    syms x;
    f = @(x) exp(2*sin(x)) - x;
    Val1 = f(x0);
    g = diff(f);
    Val2 = g(x0);
end

Answer 1

[KSSV]

function [Val1, Val2] = nonlinear1(x0)
    syms x;
    f = exp(2*sin(x)) - x;
    Val1 = f(x0);
    g = diff(f);
    Val2 = g(x0);
end

Don't use @(x)....as it is symbolic, straight away use the expression.

Answer 2

[Walter Roberson]

There are two major diff() functions in MATLAB. One of them is the numeric difference operator, roughly

 x(:, 2:end) - x(:, 1:end-1)

This is applicable only to numeric arrays. A function handle is not a numeric array so this kind of diff() does not apply to it.

The other major diff() function is part of the Symbolic Toolbox. The first parameter to it must be a symbolic array, or a symbolic function. The operation performed is calculus differentiation. A function handle is not a symbolic array and is not a symbolic function, so this kind of diff() does not apply to it.

There is no diff() function defined to operate on function handles.

What you need is

 g(x) = diff(f(x), x);