I'm kind of new to Matlab. Would anyone know how to fix this problem?

I keep getting an error with the following code:

??? Undefined function or method 'ilaplace' for input arguments of type 'double'.

% Function V
syms V real; syms s;
V = 1;
v = ilaplace(V);
pretty(v)

I know that the answer is 1/s but this error keeps coming up?

 

By defining V=1, you replace its symbolic identity and turns it into a double. You can try the following instead:

V=sym(1);