Math CentralQuandaries & Queries


Question from Julia, a student:

Prove that if a and b are coprime integers, the greatest common divisor of a + b and a - b is either 1 or 2.

Hi Julia,

I can give you a hint. If h and k are positive integers and p is a prime that divides h and k, what can you say about h + k?


About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS