how to use derivation to a function from the user

I have been suggested to use anonymous function for functions from the user and it works, but now I need to do derivation of the entered function I try diff and it's not working

str = input('Please enter the function: ', 's');
f = str2func(['@(x) ',str]);
dydx=diff(f);
r1=dydx(2);
disp(r1);

[Stephen23]

"I need to do derivation of the entered function"

Do you need a symbolic result or a numeric result?

[Manal]

both I need to display the derivative then the result of x that inputted by the user

Answer 1

[KSSV]

syms x
f = sin(x) ;
df=diff(f)

[Manal]

if I try this it will give me this error

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

[KSSV]

Did you use syms x ?

[Manal]

yes

Answer 2

[Jan]

See https://www.mathworks.com/matlabcentral/answers/312339-how-to-convert-strings-to-symbolic-expressions-without-sym for the conversion of strings to symbolical expressions.