Help Major - Logs + TI-83+

1. May 18, 2004

Keifi

Anybody know how to use a table of numbers (in the stat -> edit place) to generate a log equation...?

can you explain this step by step for me?

stat->edit place ex.

L1 L2
2 123213
4 12321312312
5 231123123123123
324 123123123123
2234 12312312321
123424 12312321
(just an example)

2. May 18, 2004

Keifi

Or can you teach me how to make a log formula without a calulator

(real data as follows)
:
Time 1:30 1:35 1:40 1:45 1:50 1:55 2:00 2:05 2:10 2:15 2:20 2:25 2:30 2:45 3:00 3:15 3:30 4:00 4:30 5:00 5:30
Difference 101 91 76 73 66 62 58 53 51 50 46 42 40 34 28 22 20 16 10 6 2

3. May 19, 2004

Simon666

You could use Taylor series for that but I have the impression that is not what you're looking for.

4. May 19, 2004

Keifi

funny thing is, i dont have any idea what you just meant... but anyways i got it.. sooooo simple i feel soo dumb :rofl: :rofl:

but anyways, a random comment :
check out the picture i made, tell me if u like

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5. May 19, 2004

Simon666

I meant this:

This calculates the natural logarithm but converges very slowly, so as I guess you want it to be calculated by hand it isn't very convenient. Nice pic, would get you a lot of female attention at Abu Ghraib. Anyway, I seem to have misunderstood your question. Sorry for that.

Last edited: May 19, 2004
6. May 19, 2004

Parth Dave

on your calculator there is lnreg (ln regression) go to:
before you use it, make sure you turn diagnostic on (go to the catalog [second --> 0]) and find the diagnostic on, and select that
stat --> calc (second tab) --> number 9 (lnreg)
it should say: LnReg on the screen
than type L1 (second --> 1) --> , (comma) --> L2 (second --> 2) --> , --> Y1 (vars --> y-vars [second tab] --> Function [number 1] --> Y1 [number 1])

this will than regress your data (L1 will by the x values, L2 will be the y values [you can use other lists also, but make sure the first one is x values the second one is y]) and give you an equation. It will than graph the equation in Y1 (you can change it to any one you want). There are many other types of regression (about 10) that you can use. Check in the manual, it has a list of every single function in the calculator. You will be able to find everything you need in it somewhere.

7. May 20, 2004

Keifi

ya thats wat i did (Parth Dave )