isi-entrance 2016 Q30

isi-entrance · India · UGA 4 marks Number Theory Prime Number Properties and Identification

Suppose $a, b$ and $n$ are positive integers, all greater than one. If $a^n + b^n$ is prime, what can you say about $n$?
(A) The integer $n$ must be 2
(B) The integer $n$ need not be 2, but must be a power of 2
(C) The integer $n$ need not be a power of 2, but must be even
(D) None of the above is necessarily true

Suppose $a, b$ and $n$ are positive integers, all greater than one. If $a^n + b^n$ is prime, what can you say about $n$?\\
(A) The integer $n$ must be 2\\
(B) The integer $n$ need not be 2, but must be a power of 2\\
(C) The integer $n$ need not be a power of 2, but must be even\\
(D) None of the above is necessarily true

Paper Questions

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