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joannabanana
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It's not only the value of z that makes z^n equals to 1! Value of n also has a part in it. For n = 0, z could be any number, even fractions. Thus z > 0 is not sufficient.joannabanana wrote:If z^n = 1, what is the value of z?
1. n is a non zero integer.
2. z > 0.
The official answer is C - both statements are needed.
My question is why isn't stmt 2 sufficient? What else could z be other than 1?
Given: z^n = 1
Statement 1: n is a non zero integer.
1 raise to any power is equal to 1 and -1 raise to any even power is also equal to 1. Thus z can be 1 for any value of n or z can be -1 for even values of n.
Not sufficient.
Statement 2: z > 0
No restrictions on n. For n = 0, z could be any number, even fractions.
Not sufficient.
1 & 2 Together: Only possible value of z is 1.
Sufficient.
The correct answer is C.
