Exponet rules

This topic has expert replies
Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Mon Oct 06, 2008 1:48 pm

Exponet rules

by msquare » Tue Oct 07, 2008 12:13 pm
I'm a little confuse can anyone explain me why

2^5 + 2^5 + 3^5 + 3^5 + 3^5 = 2^6 + 3^6 and not 13^5?

Thank you.

User avatar
Master | Next Rank: 500 Posts
Posts: 157
Joined: Tue Oct 07, 2008 5:47 am
Thanked: 3 times

by PussInBoots » Tue Oct 07, 2008 12:15 pm
2^5 + 2^5 + 3^5 + 3^5 + 3^5 = ( 2^5 + 2^5 ) + ( 3^5 + 3^5 + 3^5 ) =
2 * 2^5 + 3 * 3^5 = 2^(5+1) + 3 ^ (5+1)

Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Mon Oct 06, 2008 1:48 pm

by msquare » Tue Oct 07, 2008 12:31 pm
Thanks. Is there a rule I should know when adding numbers of different base and same exponent?

User avatar
Master | Next Rank: 500 Posts
Posts: 157
Joined: Tue Oct 07, 2008 5:47 am
Thanked: 3 times

by PussInBoots » Tue Oct 07, 2008 12:38 pm
msquare wrote:Thanks. Is there a rule I should know when adding numbers of different base and same exponent?
Nope.
Good reference: https://www.jug.net/wt/exponentrules.gif

Senior | Next Rank: 100 Posts
Posts: 62
Joined: Mon May 21, 2007 12:00 am

by vanesslondon » Wed Oct 08, 2008 6:07 am
Ok, this is tricky because it makes yuo want to use yuor exponent rules and ignore the fact that the question is about adding exponents (and remember yuo can't combine exponents when adding/subtracting).

My easy way to deal with this is to think: how many of each exponent do I have?

2 x 2^5
3 x 3^5

I set this up as 2^1 (2^5) + 3^1(3^5)

because the bases are the same you add the exponents and keep the base, so the anszer is 2^6 + 3^6.

Hope this helps!