因式分解:X15+X14+X13+X12+X11+X10+X9+X8+X7+X6+X5+X4+X3+X2+X+1
= ( x^14 )( x + 1 ) + ( x^12 )( x + 1 ) +……+ x"( x + 1 ) + ( x + 1 )
= ( x + 1 )[ ( x^14 + x^12 ) + ( x^10 + x^8 ) + ( x^6 + x^4 ) + x" + 1 ]
= ( x + 1 )[ ( x^12 )( x" + 1 ) + ( x^8 )( x" + 1 ) + ( x^4 )( x" + 1 ) + ( x" + 1 ) ]
= ( x + 1 )( x" + 1 )[ x^12 + x^8 + x^4 + 1 ]
= ( x + 1 )( x" + 1 )[ ( x^8 )( x^4 + 1 ) + ( x^4 + 1 ) ]
= ( x + 1 )( x" + 1 )( x^4 + 1 )( x^8 + 1 )第一步毛意思,