Four different integers form an increasing A.P .One of these numbers is equal to the sum of the squares of the other three numbers. Then
The product of all numbers is

Options

A. 5
B. 10
C. 20
D. 17

Answer

A, D

Explanation

`p(x)=((1-x^(2n))/(1-x^(2)))((1-x)/(1-x^(n)))=(1+x^(n))/(1+x)`
As p(x) is a polynomial , x=-1 must be a zero of `1+x^(n)`, i.e., `1+(-1)^(n)=0`. So, n must be odd.