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**diff: mclaurin's series****Guest**

please help, i dont know how to do this question, how am i supposed to differentiate a log and do i have to use the product rule aswell???

thanks, lloyd

find dy/dx where y= log e (1+x) using the mclaurin series.

(e is supposed to be subscript)

**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

To function a function into a Maclaurin series, you need to differentiate it lots of times anyway, so making that into a Maclaurin series first won't help.

Differentiating it is easy enough though.

log[sub]e[/sub] [f(x)], when differentiated, becomes f'(x)/f(x)

Applying that here gives that d(log[sub]e[/sub] (1+x))/dx = 1/(1+x).

You'd then need to differentiate that again and again until you get as many terms as you need for your series.

Why did the vector cross the road?

It wanted to be normal.

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**mikau****Member**- Registered: 2005-08-22
- Posts: 1,504

I find macluarin series problems to be a mundane task that teaches you nothing. And some of them take forever!

A teriffic waste of time I'd say...

*Last edited by mikau (2006-02-10 12:21:23)*

A logarithm is just a misspelled algorithm.

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