Factor x4+1x^4 + 1x4+1 over the field of real numbers.
(x2+1)(x2−1)(x^2+1)(x^2-1)(x2+1)(x2−1)
(x2+2x+1)(x2−2x+1)(x^2+\sqrt{2}x+1)(x^2-\sqrt{2}x+1)(x2+2x+1)(x2−2x+1)
(x2+x+1)(x2−x+1)(x^2+x+1)(x^2-x+1)(x2+x+1)(x2−x+1)
(x2+1)2(x^2+1)^2(x2+1)2