confusion with answer choice

by KK Wed Aug 13, 2008 1:41 am

Hello

I got very confused with one of the questions in OG. I am not posting the question here, but its variation to understand the answer choice.

Is 2^x + 2^-x = b ? x being an integer

one of the answer choice says......x>0 = b

what does that mean does that mean

1. x > 0 and x = b
or 2. x > 0 and 0 = b...i think this is right..

if the second is right, then for any value of x which is more than 0, 2^x + 2^-x can never be 0. so its sufficient. However the book says its insufficient. Please clarify.

by **RonPurewal** Wed Sep 17, 2008 4:58 am

heh heh, i think you just got one of the editions featuring a typographical error. i know which problem you're talking about, and, in my edition of the og, the statement in question is just "x > 0".

in other words, the "= b" is just noise, and isn't even supposed to be there in the first place.
this should become clear to you if you take a peek at the answer explanation (which will not address "b" at all) for that statement.