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#1 2007-05-24 06:31:35
- Daniel123
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- Registered: 2007-05-23
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ln
I was looking at my calculator.... what does the 'ln' button do?
thanks
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#2 2007-05-24 06:34:53
- Devantè
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- Registered: 2006-07-14
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Re: ln
[ln] is to find the natural logarithm of a number...
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#3 2007-05-24 06:36:40
- Daniel123
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Re: ln
i guess thats another thing i have to wait till next year to find out about 
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#4 2007-05-24 06:36:56
- Daniel123
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Re: ln
Thanks though!
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#5 2007-05-24 06:43:18
- Devantè
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Re: ln
Given how the natural log is described in math books, theres little "natural" about it: its defined as the inverse of e^x, a strange enough exponent already.
But theres a fresh, intuitive explanation: The natural log gives you the time needed to reach a certain amount of growth.
Lets say you have an investment in gummy bears (and who doesnt?) with interest of 100% per year, compounded continuously. If you want 10x growth, youd wait only ln(10) or 2.302 years.
The concepts are straightforward:
* e^x is the amount of continuous growth after a certain amount of time.
* Natural Log (ln) is the amount of time needed to reach a certain level of growth.
Not too bad, right?
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#6 2007-05-24 07:30:18
- lightning
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- Registered: 2007-02-26
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Re: ln
Thanks though!
what year you in
Zappzter - New IM app! Unsure of which room to join? "ZNU" is made to help new users. c:
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#7 2007-05-24 07:32:13
- luca-deltodesco
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- Registered: 2006-05-05
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Re: ln
hes in year 11 doing GCSE's
The Beginning Of All Things To End.
The End Of All Things To Come.
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#8 2007-05-24 07:57:34
- lightning
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Re: ln
11?
primary
high
coll
uni
make your pick
Zappzter - New IM app! Unsure of which room to join? "ZNU" is made to help new users. c:
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#9 2007-05-24 08:10:16
- luca-deltodesco
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- Registered: 2006-05-05
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Re: ln
what are you on about?
primary school : reception, year1 - year 4 (year 5-6)
(middle) : year 5-8
high school : (year 7-8) year 9-11 + (sixthform) year 12-13
college : equivalent year 12-13 + GCSE's + other.
uni : futher ed.
The Beginning Of All Things To End.
The End Of All Things To Come.
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#10 2007-05-24 08:31:02
- Devantè
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Re: ln
In other words, you should be aged 16 at Year 11.
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#11 2007-05-24 09:17:47
- Daniel123
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- Registered: 2007-05-23
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Re: ln
yes im in year 11.... but im not 16 yet!
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#12 2007-05-24 19:10:36
- George,Y
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- Registered: 2006-03-12
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Re: ln
Simple.
First, logs. A Log means how many times it can take you to multiply a certain number to another.
i.e.
2*2*2=8 Thus the log for 8 at the base 2 is 3
Further, fraction log is defined as this
the log for 2 at the base 8 is 1/3, Since the backward is 3. 3 times vs 1/3, pretty fair.
also we can say the log for 4 at the base 8 is 2/3, think why.
And, negative log can be defined.
the log for 1/8 at the base 2 is -3, since the log for 1/8 at the base the reciprocal of 2 is 3.
Altogether you can find that for a given base>1, a log for some number larger than it should be larger than 1
and a log for some number smaller than it but as well larger than 1 is smaller than 1 as well as positive. The log for 1 at any vaild base ,a positive number, is 0. At last, a log for some number smaller than 1 at a base larger than 1 is negative.
ln function means to calculate a log for x at a certain base.
Try to calculate ln0.5 and see if the result corresponds with a base larger than 1.
Try to calculate ln2.71828 and ln2.71829 and think what the certain base is. Can you tell a interval where it lies in?
X'(y-Xβ)=0
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