Question

Find the HCF/GCD of x^6+x^5+x^4+x^3+x^2+x+1 and x^4+x^2+x+1.

(a) x^4+x^3+x^2+1

(b) x^3+x^2+1

(c) x^2+1

(d) x^3+x^2+1

The question was posed to me during an internship interview.

This interesting question is from Polynomial and Modular Arithmetic in section Basic Concepts in Number Theory and Finite Fields of Cryptograph & Network Security

Answer 1

Correct choice is (b) x^3+x^2+1

To elaborate: Use Euclidean Algorithm and find the GCD. GCD = x^3+x^2+1.