问题
填空题
设x6=a0+a1(x-1)+a2(x-1)2+a3(x-1)3+a4(x-1)4+a5(x-1)5+a6(x-1)6,则a3=______.
答案
∵x6=[(x-1)+1]6=
+C 06
•(x-1)1+C 16
•(x-1)2+…+C 26
•(x-1)6C 66
=a0+a1(x-1)+a2(x-1)2+a3(x-1)3+a4(x-1)4+a5(x-1)5+a6(x-1)6,
∴a3=
=20.C 36
故答案为:20.