Add Scalar to Array

plus adds x to each element of the array.

syms x
A = [x sin(x) 3];
A + x

ans =
 
[ 2*x, x + sin(x), x + 3]

Add Two Matrices

Add the identity matrix to matrix M.

syms x
M = [x x^2;Inf 0];
M + eye(2)

ans =
[ x + 1, x^2]
[   Inf,   1]

Alternatively, use plus(M,eye(2)).

plus(M,eye(2))

ans =
[ x + 1, x^2]
[   Inf,   1]

Add Symbolic Functions

syms f(x) g(x)
f(x) = x^2 + 5*x + 6;
g(x) = 3*x - 2;
h = f + g

h(x) =
x^2 + 8*x + 4

Add Expression to Symbolic Function

Add expression expr to function f.

syms f(x)
f(x) = x^2 + 3*x + 2;
expr = x^2 - 2;
f(x) = f(x) + expr

f(x) =
2*x^2 + 3*x