Logarithms

[caress me down]

Anyone know how to explain this shit?

[perceptrons]

What about it? It's a rather vast topic.

[tottivillarossi]

John Napier created these if I'm not mistaken.


Napier was a very clever guy. He suspected that one of his servants was stealing from him, so one by one he locked them all in a room and told them to put their hands on this black chicken (that he carried everywhere) and this chicken would be able to tell who had 'thieving fingers'. So, they all went in one by one and put their hands on this chicken, and came out and noticed that their hands were covered in a black soot, everyone's - except for the thief.

How clever is that.

[xrawrritsalex]

i believe this is the term similar to hell.
i hate these :[ but i found a calculator at office depot (after like 20 minutes of looking) that does everything for you. so go to ur nearest office supply store and hopefully that will help.

[perceptrons]

i believe this is the term similar to hell.
i hate these :[ but i found a calculator at office depot (after like 20 minutes of looking) that does everything for you. so go to ur nearest office supply store and hopefully that will help.
Awesome way to learn...

[tonyC4L]

Logarithms really aren't hard, you just need to take a few minutes to really understand what's going on (what the base means, what the argument of the function means, etc). A log base b of a number x just means "this is the number that when you raise b to this power, you get x." Taking logarithms and exponentiating are inverse functions. That is, b^a = x implies a = log_b x.

That's the very basics of it. Do you have any questions in particular? I'd be happy to go more in depth with this.

[TotalCollapse]

They were hard when I first learned them, but they get easy.

[andrew4045]

i sucked ass at this shit

[FeynmanWannabe]

i believe this is the term similar to hell.
i hate these :[ but i found a calculator at office depot (after like 20 minutes of looking) that does everything for you. so go to ur nearest office supply store and hopefully that will help.
:hitself:

[MADSTA]

I love logarithms.
Rational functions and optimization of derivatives are another story.

[caress me down]

Thanks for help....
I absolutely despise this stuff. I handed in two almost-blank quizzes involving logarithms

[tonyC4L]

optimization using derivatives
fixed?

[MADSTA]

fixed?
Shows how much I suck at them.

[tonyC4L]

Shows how much I suck at them.
Haha it's cool, I'm just really particular about math, that's all.

[spriltsc]

I love logarithms.
Rational functions and optimization of derivatives are another story.
ya we just finished integration by parts, trig integration, and radical functions. i want to kill myself.

[Jumpoff]

Extremely easy :shrug:

x = b^y

which is

y = log (subscript)b (x)

B is hte base number that you raise to the y power and it equals x. For example,

3^2 = 9
(3 x 3 = 9)
2 = log 3 (9)

[chella182]

Ahh logarithms :-d

I do a maths degree and I still don't like em :-p I just use natural log a lot to get rid of e's in expressions.

[npmshah]

logs are simply another way to express an exponent...

an example: 2 cubed is 8 ----> 2^3=8
as a log that would be: log2 of 8 is 3

another example: 10^2 is 100

log 100= 2

whenever you see the word log WITHOUT a small number, the small number is assumed to be 10
if you want to go deeper ask me and ill give you the basic properties of logs

[tonyC4L]

whenever you see the word log WITHOUT a small number, the small number is assumed to be 10
I don't know what kind of math you do, but far more often than not, a log written without a base is assumed to be base e.

[chella182]

I don't know what kind of math you do, but far more often than not, a log written without a base is assumed to be base e.

Nah, I agree that log(whatever) without a base is base 10, and ln(whatever) is base e. That's what we get taught anyways.

[npmshah]

I don't know what kind of math you do, but far more often than not, a log written without a base is assumed to be base e.
i thought base e was represented by a natural log function
ie ln
my calculator also works this way

[tonyC4L]

Nah, I agree that log(whatever) without a base is base 10, and ln(whatever) is base e. That's what we get taught anyways.
Taken from Wolfram MathWorld (http://mathworld.wolfram.com/NaturalLogarithm.html):
"The notation ln x is used in physics and engineering to denote the natural logarithm, while mathematicians commonly use the notation log x"

Even as a math major, I personally use ln to denote a natural log when I do my own work, so there is no confusion (like there is now). However, many of my teachers use log x in lectures, and it's always assumed to be base e. Also, the three (arguably) most popular computer algebra systems (Maple, Mathematica, and MATLAB) all use log to refer to the natural logarithm. Any other base (including 10) is identified with an additional argument.

[perceptrons]

Well, after like pre-calc, you never do anything but the natural log (base e) anyway, that's probably what Tony is talking about.

[chella182]

Taken from Wolfram MathWorld (http://mathworld.wolfram.com/NaturalLogarithm.html):
"The notation ln x is used in physics and engineering to denote the natural logarithm, while mathematicians commonly use the notation log x"

Even as a math major, I personally use ln to denote a natural log when I do my own work, so there is no confusion (like there is now). However, many of my teachers use log x in lectures, and it's always assumed to be base e. Also, the three (arguably) most popular computer algebra systems (Maple, Mathematica, and MATLAB) all use log to refer to the natural logarithm. Any other base (including 10) is identified with an additional argument.
I've used ln in Maple before I'm sure...

[ChelseaRiane]

kill me.
logarithms make me sick

[chella182]

Useful in a part of Statistics I'm doing at the moment though ^_^ make it a lot easier, oddly!

[tonyC4L]

I've used ln in Maple before I'm sure...
It recognizes both. Matlab and Mathematica do not recongize it though, I don't think.

[chella182]

It recognizes both. Matlab and Mathematica do not recongize it though, I don't think.
Fair enough. I'm not sure we ever use Matlab at uni... Not a fan of those computer program stuff in maths :stickout: had a nightmare with a program called R this semester!

[tonyC4L]

Fair enough. I'm not sure we ever use Matlab at uni... Not a fan of those computer program stuff in maths :stickout: had a nightmare with a program called R this semester!
Funny, I'm using R this quarter too for a probability class. It's not so bad, but I have a feeling that the stuff we do is very basic so I might be deceived.

[chella182]

Funny, I'm using R this quarter too for a probability class. It's not so bad, but I have a feeling that the stuff we do is very basic so I might be deceived.
The stuff we're doing is ridiculous.

Btww, I looove your avatar - Dexter is immense ^_^

[KillTheMusic]

It recognizes both. Matlab and Mathematica do not recongize it though, I don't think.

Matlab doesn't recognize ln. log(x) for natural log and log10(x) for base 10.

Fair enough. I'm not sure we ever use Matlab at uni... Not a fan of those computer program stuff in maths :stickout: had a nightmare with a program called R this semester!

Matlab is awesome once you learn how to use it. The amount of stuff you can do with it is ridiculous. Can't speak for the other programs, though.

[tonyC4L]

The stuff we're doing is ridiculous.

Btww, I looove your avatar - Dexter is immense ^_^
Thanks, it really is a great show. I am so excited for Season 3 Blu-ray and Season 4.

Matlab doesn't recognize ln. log(x) for natural log and log10(x) for base 10.
Yeah that's what I said.

[chella182]

Thanks, it really is a great show. I am so excited for Season 3 Blu-ray and Season 4.
I've seen Season 3 online ^_^ since we're only up to season 2 here :( I'll watch season 4 as and when it gets uploaded on the 'net though. OR I'll just download it when it's finished :stickout:

[perceptrons]

MATLAB's ability is great, but I hate it's syntax.

[chella182]

I just hate R in general :stickout: I do get that it can do some amazing stuff, but I really don't care enough about it enough to learn complicated syntax and stuff.