Math Q, How to Find the Power?

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Post » Tue Jan 18, 2011 7:48 pm

Hey, how do I find the power of something?

I have a base number, let's say it's 10 and 10 to the power of 2 is 100.

How could I have the sum (100) and the base (10) and get 2?

or 4 to the power of 3 = 64

So I'd have 4 and 64 and get 3?
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Post » Tue Jan 18, 2011 8:18 pm

Is this what you're after?

[url:eq7jhs0r]http://sourceforge.net/apps/mediawiki/construct/index.php?title=Expressions[/url:eq7jhs0r]
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Post » Tue Jan 18, 2011 9:31 pm

No,

from the page:

^ Raise to power 8 ^ 2 (= 64)

I have the 8 and the 64, I need to be able to find out the 2

Thanks though.
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Post » Tue Jan 18, 2011 9:38 pm

I belive its called root. Lets say 10 ^2 = 100(10 to the power of 2 = 10^2). To get 10 would be the key ^ to (1/2):
100^(1/2) = 10.
To get 3 from 4 and 64: 64^(1/4) = 3
so its x^(1/n) where x is the sum and n the number, to get the power.

Hope this helped :)
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Post » Tue Jan 18, 2011 9:57 pm

Clever way to get your math homework done, isn't it.
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Post » Wed Jan 19, 2011 10:02 am

What you're trying to find is the logarithm, not the power.

For 8^2 = 64, 8 is the base, 64 is the power and 2 is the exponent. The exponent equals the logarithm of the power as long as you don't change the base.

http://sourceforge.net/apps/mediawiki/c ... xpressions <-- Look under "Math".

Use ln for base e (Euler's number, approx. 2.718) or log for base 10.

For example: 10^x = 1000. To find x, just do: [code:3jalj99k]log(1000)[/code:3jalj99k]
...which gives you 3.

If the base isn't 10 or e, use this instead: [code:3jalj99k]log(power) / log(base)[/code:3jalj99k]
(You can use ln instead of log, the result should be the same.)

Using the example above, 8^2 = 64, you get [code:3jalj99k]log(64) / log(8)[/code:3jalj99k]
...and that should give you 2.
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Post » Thu Jan 20, 2011 1:54 am

log is what you need as the above poster mentioned



this is what it does, but you need to use the change of base relation



the base k used doesnt matter, so ln or log (base 10) can be used interchangeably
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Post » Thu Jan 20, 2011 2:43 am

Quasi, seems that site hates hotlinking.
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Post » Thu Jan 20, 2011 2:39 pm

Awesome! Thanks everybody!
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