(x+1)2+(x+1)11=a0+a1(x+2)+a2(x+2)2+…+a10(x+2)10+a11(x+2)11,则a1=( ) A.-12 B.-10 C.9 D.11
问题描述:
(x+1)2+(x+1)11=a0+a1(x+2)+a2(x+2)2+…+a10(x+2)10+a11(x+2)11,则a1=( )
A. -12
B. -10
C. 9
D. 11
答
(x+1)2+(x+1)11=[(x+2)-1]2+[(x+2)-1]11,
则a1=
(-1)+
C
12
(-1)10=-2+11=9,
C
1011
故选C.