问题
选择题
(x-1)5+5(x-1)4+10(x-1)3+10(x-1)2+5(x-1)等于( )
A.x5-1
B.x5
C.x5+1
D.(x-1)5-1
答案
原式=C50(x-1)5+C51(x-1)4+C52(x-1)3+C53(x-1)2+C54(x-1)+C55-1
=[1+(x-1)]5-1=x5-1
故选A.
(x-1)5+5(x-1)4+10(x-1)3+10(x-1)2+5(x-1)等于( )
A.x5-1
B.x5
C.x5+1
D.(x-1)5-1
原式=C50(x-1)5+C51(x-1)4+C52(x-1)3+C53(x-1)2+C54(x-1)+C55-1
=[1+(x-1)]5-1=x5-1
故选A.