If n is a positive integer, then (√3+1)^2n - (√3-1)^2n is

If n is a positive integer, then (√3+1)2n - (√3−1)2n is

  1. An even positive integer
  2. A rational number other than positive integers
  3. An odd positive integer
  4. An irrational number

Solution

Since n is a positive integer, assume n = 1. You are not required to solve the question.

(√3+1)2 - (√3−1)2

Use (x+y)2 = x2 + 2xy + y2

= (3 + 2√3 + 1) - (3 - 2√3 + 1)

= 4√3, which is irrational number.

Correct option is D.