Freshman's Dream

The freshman's dream is a name for the mistake:
 * $$\left({x + y}\right)^n = x^n + y^n$$

where $$n$$ is a real number.

The correct result is given by the Binomial Theorem.

Note, however, the result given in Prime Power of Sum Modulo Prime, which is:
 * $$\left({a + b}\right)^p \equiv a^p + b^p \pmod p$$

where $$p$$ is a prime number.

This is also sometimes called the "freshman's dream", but this one is in fact true.