MATLAB isequal function gives wrong answer for symbolic expression

Question

In the following simple code:

syms x
isequal((x+1)^2, x^2+2*x+1)

MATLAB returns false, but two expressions are same! What is wrong with the code?

Answer 1

These are not exactly the same expressions, and isequal() tests for expression equality. Try for example:

>> isequal(expand((x+1)^2), x^2+2*x+1)

ans =

  logical

   1

or,

>> isequal(simplify((x+1)^2), simplify(x^2+2*x+1))

ans =

  logical

   1

PS you could also use isAlways() to compare expressions,

isAlways((x+1)^2 == x^2+2*x+1)

ans =

  logical

   1