Calculator overflow

gcd ( 2 110 1 , 2 20 1 ) = ? \large \text{gcd}(2^{110} - 1,2^{20} - 1) = \ ?


The answer is 1023.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Jaleb Jay
Nov 11, 2015

You can quickly take note that gcd(110,20)=10. With this you can substitute 2 10 = x 2^{10}=x . Doing this gives the values of g c d ( x 11 1 , x 2 1 ) gcd(x^{11}-1,x^2-1) . Factoring both expressions we find: x 11 1 = ( x 10 + x 9 + . . . + x + 1 ) ( x 1 ) x 2 1 = ( x + 1 ) ( x 1 ) x^{11}-1=(x^{10}+x^9+...+x+1)(x-1) \\ x^2-1=(x+1)(x-1) Notice that both expressions share a factor of x 1 = 2 10 1 = 1023 x-1=2^{10}-1=1023

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...