분해 인수:x15+x14+x13+...+x2+x+1.

분해 인수:x15+x14+x13+...+x2+x+1.

(x8)2-1=(x8)2-1=(x8+1)(x8+1)(x8+1)=(x8+1)[(x4)2-1]=(x8+1)(x8+1)(x4+1)(x2+1)(x2+1)(x2-1)=(x8+1)(x8+1)(x4+1)(x4+1)(x2+ 1)(x 2+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+1)(x+  x−1,=(x8+1)(x4+1)(x2+1)(x+1);