Find the greatest common divisor

Find the greatest common divisor of a = 102 4 2014 1 a=1024^{2014}-1 and b = 102 4 2014 + 1023 b=1024^{2014}+1023 .


The answer is 1.

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.

2 solutions

Maryam Malik
Apr 6, 2014

( 102 4 2014 + 1023 , 102 4 2014 1 ) = ( 102 4 2014 + 1023 102 4 2014 + 1 , 102 4 2014 1 ) = ( 1024 , 102 4 2014 1 ) = ( 1024 , 102 4 2014 1 ) m o d ( 1024 ) = ( 0 , 1 ) m o d ( 1024 ) = ( 1024 , 1023 ) = 1 (1024^{2014}+1023,1024^{2014}-1)=(1024^{2014}+1023-1024^{2014}+1,1024^{2014}-1)=(1024,1024^{2014}-1)=(1024,1024^{2014}-1)mod(1024)= (0,-1)mod(1024)=(1024,1023)=1

Adrian Neacșu
Apr 5, 2014

Let's say that gcd(a,b)=d. Then d|a and d|b. Therefore d|b-a=1024. So d|1024, then d can be 1, 2, 4, 8,..., 512, 1024. Of course 1 divides both a and b. For d>1 d can only be a even number, but a and b are odd numbers, so d>1 can't be a divisor for a and b. The only divisor is 1.

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...