解答
展开 (3x+x4.5)8
解答
6561x8+78732x6+413343x4+1240029x2+818600435+4x211160261+16x433480783+16x614348907+256x843046721
求解步骤
(3x+x4.5)8
使用二项式定理: (a+b)n=i=0∑n(in)a(n−i)bia=3x,b=x4.5
=i=0∑8(i8)(3x)(8−i)(x4.5)i
展开求和
=0!(8−0)!8!(3x)8(x4.5)0+1!(8−1)!8!(3x)7(x4.5)1+2!(8−2)!8!(3x)6(x4.5)2+3!(8−3)!8!(3x)5(x4.5)3+4!(8−4)!8!(3x)4(x4.5)4+5!(8−5)!8!(3x)3(x4.5)5+6!(8−6)!8!(3x)2(x4.5)6+7!(8−7)!8!(3x)1(x4.5)7+8!(8−8)!8!(3x)0(x4.5)8
化简 0!(8−0)!8!(3x)8(x4.5)0:6561x8
化简 1!(8−1)!8!(3x)7(x4.5)1:78732x6
化简 2!(8−2)!8!(3x)6(x4.5)2:413343x4
化简 3!(8−3)!8!(3x)5(x4.5)3:1240029x2
化简 4!(8−4)!8!(3x)4(x4.5)4:818600435
化简 5!(8−5)!8!(3x)3(x4.5)5:6x216740391.5
化简 6!(8−6)!8!(3x)2(x4.5)6:2x44185097.875
化简 7!(8−7)!8!(3x)1(x4.5)7:x6896806.6875
化简 8!(8−8)!8!(3x)0(x4.5)8:x8168151.25390…
=6561x8+78732x6+413343x4+1240029x2+818600435+6x216740391.5+2x44185097.875+x6896806.6875+x8168151.25390…
化简 6561x8+78732x6+413343x4+1240029x2+818600435+6x216740391.5+2x44185097.875+x6896806.6875+x8168151.25390…:6561x8+78732x6+413343x4+1240029x2+818600435+4x211160261+16x433480783+16x614348907+256x843046721
=6561x8+78732x6+413343x4+1240029x2+818600435+4x211160261+16x433480783+16x614348907+256x843046721