The difference between Feval and eval in MATLAB __metlab

Feval and Eval run one of the differences: FEVAL FN must not be an expression. Feval's FN only accepts
The name of the function. function eval gives Matlab the ability to provide macros. Where the function provides a user-created
Function name to the other function so that the value can be evaluated.
The function feval is similar to eval, but there are more restrictions on usage. Feval (' fun ', x) by string '
Fun ' given function value, its input parameter is variable x. That is, Feval_r (' fun ', X) is equivalent to finding fun (x)
Value.

Format Short

X=pi/4;

ve=eval (' 1+sin (x) ')

Ve =

1.7071  

vf=feval (' 1+sin (x) ', x)

??? The Error using ==> feval Invalid function name ' 1+sin (x) '.