解答
展开 (x+6)20
解答
x20+120x19+6840x18+246240x17+6279120x16+120559104x15+1808386560x14+21700638720x13+211581227520x12+1692649820160x11+1.11715E13x10+6.09354E13x9+612⋅125970x8+613⋅77520x7+614⋅38760x6+615⋅15504x5+616⋅4845x4+617⋅1140x3+618⋅190x2+619⋅20x+620
求解步骤
(x+6)20
使用二项式定理: (a+b)n=i=0∑n(in)a(n−i)bia=x,b=6
=i=0∑20(i20)x(20−i)⋅6i
展开求和
=0!(20−0)!20!x20⋅60+1!(20−1)!20!x19⋅61+2!(20−2)!20!x18⋅62+3!(20−3)!20!x17⋅63+4!(20−4)!20!x16⋅64+5!(20−5)!20!x15⋅65+6!(20−6)!20!x14⋅66+7!(20−7)!20!x13⋅67+8!(20−8)!20!x12⋅68+9!(20−9)!20!x11⋅69+10!(20−10)!20!x10⋅610+11!(20−11)!20!x9⋅611+12!(20−12)!20!x8⋅612+13!(20−13)!20!x7⋅613+14!(20−14)!20!x6⋅614+15!(20−15)!20!x5⋅615+16!(20−16)!20!x4⋅616+17!(20−17)!20!x3⋅617+18!(20−18)!20!x2⋅618+19!(20−19)!20!x1⋅619+20!(20−20)!20!x0⋅620
化简 0!(20−0)!20!x20⋅60:x20
化简 1!(20−1)!20!x19⋅61:120x19
化简 2!(20−2)!20!x18⋅62:6840x18
化简 3!(20−3)!20!x17⋅63:246240x17
化简 4!(20−4)!20!x16⋅64:6279120x16
化简 5!(20−5)!20!x15⋅65:120559104x15
化简 6!(20−6)!20!x14⋅66:1808386560x14
化简 7!(20−7)!20!x13⋅67:21700638720x13
化简 8!(20−8)!20!x12⋅68:211581227520x12
化简 9!(20−9)!20!x11⋅69:1692649820160x11
化简 10!(20−10)!20!x10⋅610:36288004.05391E19x10
化简 11!(20−11)!20!x9⋅611:3628802.21122E19x9
化简 12!(20−12)!20!x8⋅612:612⋅125970x8
化简 13!(20−13)!20!x7⋅613:613⋅77520x7
化简 14!(20−14)!20!x6⋅614:614⋅38760x6
化简 15!(20−15)!20!x5⋅615:615⋅15504x5
化简 16!(20−16)!20!x4⋅616:616⋅4845x4
化简 17!(20−17)!20!x3⋅617:617⋅1140x3
化简 18!(20−18)!20!x2⋅618:618⋅190x2
化简 19!(20−19)!20!x1⋅619:619⋅20x
化简 20!(20−20)!20!x0⋅620:620
=x20+120x19+6840x18+246240x17+6279120x16+120559104x15+1808386560x14+21700638720x13+211581227520x12+1692649820160x11+36288004.05391E19x10+3628802.21122E19x9+612⋅125970x8+613⋅77520x7+614⋅38760x6+615⋅15504x5+616⋅4845x4+617⋅1140x3+618⋅190x2+619⋅20x+620
化简 x20+120x19+6840x18+246240x17+6279120x16+120559104x15+1808386560x14+21700638720x13+211581227520x12+1692649820160x11+36288004.05391E19x10+3628802.21122E19x9+612⋅125970x8+613⋅77520x7+614⋅38760x6+615⋅15504x5+616⋅4845x4+617⋅1140x3+618⋅190x2+619⋅20x+620:x20+120x19+6840x18+246240x17+6279120x16+120559104x15+1808386560x14+21700638720x13+211581227520x12+1692649820160x11+1.11715E13x10+6.09354E13x9+612⋅125970x8+613⋅77520x7+614⋅38760x6+615⋅15504x5+616⋅4845x4+617⋅1140x3+618⋅190x2+619⋅20x+620
=x20+120x19+6840x18+246240x17+6279120x16+120559104x15+1808386560x14+21700638720x13+211581227520x12+1692649820160x11+1.11715E13x10+6.09354E13x9+612⋅125970x8+613⋅77520x7+614⋅38760x6+615⋅15504x5+616⋅4845x4+617⋅1140x3+618⋅190x2+619⋅20x+620