[問題]GMATPrep DS意料外的答案

[unwindedson]

Z^n=1, what is the value of z?
(1)n is an nonzero integer
(2)z>0

答案是C
我寫A
Z^n=1, n=...-3, -2, -1, 1, 2, 3... =>z=1
if z=-1 => Z^n=1 or -1

是我少考慮ㄌ什ㄇ?
any idea?

[cohika]

Z^n=1, what is the value of z?
(1)n is an nonzero integer
(2)z>0

答案是C
我寫A
Z^n=1, n=...-3, -2, -1, 1, 2, 3... =>z=1
if z=-1 => Z^n=1 or -1

是我少考慮ㄌ什ㄇ?
any idea?

(1) n=2 , z=1,-1 不充分
(2) n=0 , z= any positive value 不充分

[unwindedson]

感恩，
我想我誤解題目意思，把n當成任一非零整數