若n是正整数,有理数x、y满足x+1y=0,则一定成立的是(  ) A.x2n+1+(1y)n=0 B.x2n+1+(1y)2n+1=0 C.x2n+(1y)2n=0 D.xn+(1y)2n=0

问题描述:

若n是正整数,有理数x、y满足x+

1
y
=0,则一定成立的是(  )
A. x2n+1+(
1
y
n=0
B. x2n+1+(
1
y
2n+1=0
C. x2n+(
1
y
2n=0
D. xn+(
1
y
2n=0

∵有理数x、y满足x+

1
y
=0,
∴x与
1
y
互为相反数.
∴x2n+1+(
1
y
2n+1=0,x2n+(
1
y
2n=2x2n或2×(
1
y
2n
故选B.