Get the derivative of a function_handle in MATLAB

Question

Is it possible to get the derivative of a function_handle as a other function_handle ?

Like:

  fun1 = @(x) x^2;
  % do that ...
  disp(fun2);
    @(x) x*2

I know how to find the derivative of a symbolic function but I can't convert a function_handle to a symbolic function.

I'm new to matlab and I couldn't find any way on doing that. Thanks in advance.

Answer 1

The short answer is "No." MATLAB has no idea what the contents of the function_handle mean in a symbolic sense. You're better off creating it using syms in first place.

A longer answer would be either to use the Symbolic Math Toolbox, as suggested by @A Danesh, or an approximation, as suggested by @Andrey.

However, if you're always working with polynomials, then you can store the coefficients as an array and use the following functions:

• polyval to evaluate
• conv to multiply
• deconv to divide
• polyder to differentiate
• polyint to integrate

Answer 2

syms x 
f = @(x) x^2 + 1; 
diff(f,x)

Ans:

2*x + 1

Answer 3

You can get an approximation function:

 delta = 0.0001;
 d = @(x)( (fun1(x+delta) - fun1(x))./delta)

Answer 4

you can't analytically from a function handle.

but if you got the symbolic math toolbox you can derivate the symbolic function and create a function handle from the result.