已知(1/4+2x)^n的展开式中前三项的二项式系数的和等于37.求展开式中二
已知(1/4+2x)^n的展开式中前三项的二项式系数的和等于37.求展开式中二
数学人气:128 ℃时间:2019-09-29 01:14:53
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二项式系数为C(n,0),C(n,1),C(n,2),...C(n,n),.前三项和为37,即1+n+n(n-1)/2=37,得 n=8C(8,0),C(8,1),C(8,2),...C(8,8),中C(8,4)最大.所以那一项为C(8,4)*(1/4)^4(2x)^4=(35/8)x^4系数为35/8....
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