Determine all pairs of positive integers \(m,n\) such that \(2^m + 3^n\) is a perfect square.

Source: *Problem Primer for the Olympiad*

No vote yet

11 votes

×

Problem Loading...

Note Loading...

Set Loading...

## Comments

Sort by:

TopNewestA brief sketch: Considering modulo \(3, m\) must be even. Considering modulo \(4, n\) must be even. Thus we have a primitive pythagorean triple, and so we have \( 2xy = 2^{m/2} \) and \(x^2- y^2 = 3^{n/2}\). This I believe is easily solved and leads to the only solution being \(m=4,n=2\) (If I haven't made a mistake).

Log in to reply

But also m=0 and n=1 is a solution !!

Log in to reply

The problem asks for "all pairs of positive integers \(m,n\)". The number \(0\) is not positive.

Log in to reply

That's right, well done :)

Log in to reply

Thank you for posting such a nice problem!

Log in to reply

Log in to reply

This problem is from Indian National Mathematical Olympiad

Log in to reply