logs (1 Viewer)

[Nichola]

Okay I was wondering if anyone could help me with this:

Find the derivative of:

e^(5x - 2)

Do you do the natural log of e or what? I'm lost! This log stuff really confuses me!

Thanks for your time,
Nic

 

[kini mini]

Originally posted by Nichola
Okay I was wondering if anyone could help me with this:

Find the derivative of:

e^(5x - 2)

Do you do the natural log of e or what? I'm lost! This log stuff really confuses me!

Thanks for your time,
Nic

Hi Nichola

There is no need to do the natural log of e. Just remember that the derivative of any function e^f(x) is f'(x).e^f(x) - all you have to do is put the derivative of the exponent of e in front of the original function. So the answer is 5e^(5x - 2).

This assumes you are differentiating with respect to the same variable as the one in the exponent of e.

Hmmm, nice to see someone's doing some holiday revison . Don't worry if logs confuse you at first, do enough of them and they will become your friends .

 

[Nichola]

Thanks for all your help, Kini Mini and Bon! It's a lot clearer now. Our teacher said we were meant to have done basic logs in year 10, but we didn't, so I guess we didn't have that basic grounding.

Kini, we have to maths revision in the holidays Because our teacher insists it could make or break our HSC! Eek! It looks as though I'm going to have no holidays!

Thanks again,
Nic

 

[kini mini]

Originally posted by Nichola
Thanks for all your help, Kini Mini and Bon! It's a lot clearer now. Our teacher said we were meant to have done basic logs in year 10, but we didn't, so I guess we didn't have that basic grounding.

Kini, we have to maths revision in the holidays Because our teacher insists it could make or break our HSC! Eek! It looks as though I'm going to have no holidays!

Thanks again,
Nic

You're welcome . I remember doing logs in year 10, but I seem to remember that it was not set down in the sylabus that they absolutely had to be done then, but def in year 11 . If your school stuffs up like that then holiday revision is definitely the way to go!

Make sure you get a good holiday though, it only gets harder from here. A few hours of work every day should be enough, no need to sit up all night or anything. This time last year I was doing...bugger all actually LOL! I read the texts and some cribs for english, read the French papers, flicked thru the sci books...it was January before I actually did any seriosu work. If you do it will help you a lot though, the first few weeks of school are much easier.

 

[professor]

ok, i can get the basic log...but one question, what is 'ln' sorri for being stupid, i'm try to do some self study over the holidays coz our school is soooooooooo behind. Also, whats the relation between ln and log

 

[flyin']

Originally posted by professor
ok, i can get the basic log...but one question, what is 'ln' sorri for being stupid, i'm try to do some self study over the holidays coz our school is soooooooooo behind. Also, whats the relation between ln and log

ln - log base 'e' (also known as the natural log)
log - log base 10 ...

relation between ln and log ... i honestly dont know ...

 

[BlackJack]

log(10) x = ln / ln10
That is,
log(a) x = log(b) x / log(b) a

Be careful, because a log by itself actually means base e as well in many texbooks. It's probably on some calculators that have 'log' with base 10.

 

[kini mini]

Pender's book uses log to mean log base 'e'.