a4(x+1)4+a3(x+1)3+a2(x+1)2+a1(x+1)+a0=x4,则a3-a2+a1=_.
问题描述:
a4(x+1)4+a3(x+1)3+a2(x+1)2+a1(x+1)+a0=x4,则a3-a2+a1=______.
答
[(x+1)-1]4=C40(x+1)4-C41(x+1)3+C42(x+1)2-C43(x+1)+C44,
又由题意,[(x+1)-1]4=a4(x+1)4+a3(x+1)3+a2(x+1)2+a1(x+1)+a0,
则a3=-C41,a2=C42,a1=-C43,
有a3-a2+a1=(-C41)-C42+(-C43)=-14.
答案:-14