Questions about the world of GMAT Math from other sources and general math related questions.
oreoandmilk2004
Course Students
 
Posts: 7
Joined: Wed Dec 31, 1969 8:00 pm
 

Faster way to compute or estimate (1.02)^4?

by oreoandmilk2004 Wed Oct 10, 2012 4:25 am

I came across one of the OG problems that ask us to compute this (1.02)^4 as part of the answers, but it took me quite a bit after computing (1.02)^2 =1.0404 and then 1.0404 by 1.0404, I wonder if there is a faster way I can estimate this.

I would greatly appreciate any insight!

Thanks!
tim
Course Students
 
Posts: 5665
Joined: Tue Sep 11, 2007 9:08 am
Location: Southwest Airlines, seat 21C
 

Re: Faster way to compute or estimate (1.02)^4?

by tim Thu Oct 11, 2012 2:32 am

a quick and pretty close estimate for raising a number really close to 1 to a higher power is to multiply the excess (in this case .02) by the power (.02*4 = .08) and add it to 1, so in this case 1.08 is a pretty good estimate..
Tim Sanders
Manhattan GMAT Instructor

Follow this link for some important tips to get the most out of your forum experience:
https://www.manhattanprep.com/gmat/forums/a-few-tips-t31405.html
oreoandmilk2004
Course Students
 
Posts: 7
Joined: Wed Dec 31, 1969 8:00 pm
 

Re: Faster way to compute or estimate (1.02)^4?

by oreoandmilk2004 Thu Oct 11, 2012 2:55 am

Thanks, Tim. Would this technique only work for those numbers close to one? I wonder if we could expand this to other numbers...
tim
Course Students
 
Posts: 5665
Joined: Tue Sep 11, 2007 9:08 am
Location: Southwest Airlines, seat 21C
 

Re: Faster way to compute or estimate (1.02)^4?

by tim Thu Oct 11, 2012 3:43 am

only for numbers close to 1 and relatively small powers. the farther you are from 1, and the larger the power is, the more the estimate will deviate from the correct answer..
Tim Sanders
Manhattan GMAT Instructor

Follow this link for some important tips to get the most out of your forum experience:
https://www.manhattanprep.com/gmat/forums/a-few-tips-t31405.html