by rohit801 Sat Feb 16, 2008 6:00 pm
[deleted b/c poster did not cite author]
look at it this way: it is clear that X + X = 2X, right- u are adding the same thing two times, so it is 2 times that thing.
in this case the expression is 2^X and that is being added twice, right? so, it becomes 2 * 2 ^x.
Now, 2 means 2^1 [2^2=4 etc]. now, we have 2^1 * 2 ^x. what do we see here- same BASE [2] being multiplied with exponents. so, we can ADD the powers [just as we can SUBTRACT the exponents when division is concerned]. so, it becomes BASE ^ [add exponenets] = 2 ^ x+1.
does that help?