OK, I'm in Pre-Calc and I usually am good at Math (my fav subject..) and all that but I was sick the day this was taught, my teacher doesn't seem to want to help much, and the textbook is confusing me even more... I need help! :ermm:

Luckily, you can get a perfect homework grade for attempting the work :D , but I need to learn this stuff before the test comes along...

Anybody want to explain what the heck Log and Ln are and what I'm supposed to do with them? :blink:

My favorite...
Logs are cut pieces of wood, mainly used in... wait... they're like reverse exponents, sort of. Here's the format...
log (subscript)2 32=5. Because 2^5=32. That's read "logarithm, base two, of 32 equals 5".
log (subscript)5 25=2. Because 5^2=25. Get the idea? The base to the power of the answer.
log (subscript)x 16=4. x^4=16. x=2.
log (subscript)10 x=100. 10^x=100. x=2.
log (subscript)2 x=32. 2^32=x. x=4294967296. Get it?

The natural log (ln) involves the pi-like number, "e".. It's the same idea... I'd write out an explanation, but this site does a pretty good job Ask Dr. Math. ln is more useful when graphing logarithmic functions.

Hope that gives you the basics!
Edit: Oh! And when you use "log" on your calculator, it's automatically to the base 10. To convert between them, do like this...
log (base)2 32=x: (log 32)/(log 2). The log of the number after the base over the log of the base.

Well done Bo.
I want to emphasize what he said about them being reverse exponents. They are reverse exponents.
If I took 4^3 I would get 64. Well, if I took the log base 4 of 64, I would get 3.

A logorithm is just saying what power would you have to take this base to, to get this number. The base is the little subscript under the "log", and the number is what comes right after the log.

Let's say you wanted to find out what power you needed to take 2 to, to get 256. It's the reverse exponent! You need to take the log base 2 of 256. And, if you do it on your calculator, voila, you get 8.

Since a log is the reverse exponent, you can undo exponentiation with logorimentation (I think I just made up that word), or vice-versa.
10^(log(x)) = x and log(10^x) = x
Same goes for LN. e^(ln(x)) = x and ln(e^x) = x

I hope that furthered your understanding. If you still don't get it, just give us a ring :)

:D Thanx Guys!!!! :D

Maybe I won't flunk the next test after all... :r

Edit: I'm an idiot, I didn't read through it all and didn't see the "e" portion. Oh well, we're on Polar Coordinates now in Pre-Calc.

Polar Coordinates :s
I never liked those, except that you can make cool pictures with it on a graphing calculator :lol: