Integer Part or Limit Involving Conjugate Surd Binomial Expansions
The question involves computing the integer part (floor), a limit, or an exact expression for (a+√b)^n by exploiting the conjugate (a−√b)^n, where the conjugate is small.
If $n$ is a positive integer, then $(\sqrt{3}+1)^{2n} - (\sqrt{3}-1)^{2n}$ is (1) an irrational number (2) an odd positive integer (3) an even positive integer (4) a rational number other than positive integers