mersenneforum.org problem 2.4
 Register FAQ Search Today's Posts Mark Forums Read

 2014-08-20, 22:34 #1 MattcAnderson     "Matthew Anderson" Dec 2010 Oregon, USA 23·149 Posts problem 2.4 Hi Math People, Here is another problem from Terence Tao's book Solving Mathematical Problems. Problem 2.4 states - Find all solutions of 2^n + 7 = x^2, where n and x are integers. This one is a little tricky. Regards, Matt
 2014-08-20, 22:57 #2 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 1005310 Posts Only one solution: n=1, x=3. Consider the equation, modulo 8.
 2014-08-21, 03:26 #3 axn     Jun 2003 22·32·151 Posts n = 1, x = -3 ?
 2014-08-21, 04:10 #4 Batalov     "Serge" Mar 2008 Phi(4,2^7658614+1)/2 32×1,117 Posts Right, right. |x|=3.
 2014-08-21, 04:40 #5 MattcAnderson     "Matthew Anderson" Dec 2010 Oregon, USA 23×149 Posts That is correct. Batalov and Axn are smart cookies. Regards, Matt

 Similar Threads Thread Thread Starter Forum Replies Last Post didgogns Msieve 1 2016-11-15 03:31 science_man_88 Miscellaneous Math 2 2010-10-10 16:36 derekg Lone Mersenne Hunters 2 2007-02-26 22:47 Neves Miscellaneous Math 5 2004-02-10 22:59 Neves Puzzles 15 2004-02-05 23:11

All times are UTC. The time now is 07:10.

Tue Jan 31 07:10:54 UTC 2023 up 166 days, 4:39, 0 users, load averages: 0.84, 0.92, 0.93