6^x=4 ? i have a sudden black out and i can't remember the rule for when solving equations like this one.. to complicate things i'm not allowed to answer with x=log4/log6

Results 1 to 15 of 16

- Feb 11th 2008, 01:10 PM #1

- Joined
- Jan 2008
- Posts
- 77

- Feb 11th 2008, 02:03 PM #2

- Joined
- Dec 2007
- From
- University of California, Berkeley
- Posts
- 48

- Feb 11th 2008, 02:05 PM #3

- Joined
- Jan 2008
- Posts
- 77

- Feb 11th 2008, 02:08 PM #4

- Feb 11th 2008, 02:10 PM #5

- Joined
- Jan 2008
- Posts
- 77

- Feb 11th 2008, 02:11 PM #6

- Joined
- Dec 2007
- From
- University of California, Berkeley
- Posts
- 48

- Feb 11th 2008, 02:13 PM #7

- Feb 11th 2008, 02:14 PM #8

- Joined
- Jan 2008
- Posts
- 77

- Feb 11th 2008, 02:19 PM #9
__Method1:__

Initial equation

Take the log of both sides (it doesn't matter what base you use)

One of the properties of logs is that if they are the log of a number to a power, they are the same as the power times the log of the number. Meaning so

Divide both sides by log(6)

__Method2__

Initial equation

Take log base 6 of both sides

Simlify

Use change of base formula to rewrite in a format you can plug into a calculator. Change of base formula says This works for any value of c. Typically the value chosen is 10 or e, as log base ten and log base e (natural log) are the two most common logs, and are programmed into any decent calculator.

- Feb 11th 2008, 02:21 PM #10

- Feb 11th 2008, 02:28 PM #11

- Joined
- Oct 2007
- Posts
- 158

- Feb 11th 2008, 02:31 PM #12

- Joined
- Jan 2008
- Posts
- 77

- Feb 11th 2008, 02:32 PM #13
Then the answer he is looking for is

0.77370561446908317374049227693595

Which is not exact, and I would seem to require a calculator to find.

It seems most likely to me that they are looking for or as these values are exact, and one of the other requirements was that he could not use a calculator.

- Feb 11th 2008, 02:34 PM #14

- Joined
- Oct 2007
- Posts
- 158

- Feb 11th 2008, 02:35 PM #15

- Joined
- Oct 2007
- Posts
- 158