Define the symbolic function x + y. First, create the function by using syms. Then define the function.

syms f(x,y)
f(x,y) = x + y

f(x, y) =
x + y

f(1,2)

ans =
3

syms x y
f = symfun(x+y,[x y])

f(x, y) =
x + y

Return the body of a symbolic function by using formula. You can use the body for operations such as indexing into the function. Return the arguments of a symbolic function by using argnames.

syms f(x,y)
f(x,y) = [x^2, y^4];

fbody = formula(f);
fbody(1)
fbody(2)

ans =
x^2
ans =
y^4

fvars = argnames(f)

fvars =
[ x, y]