
#1
Oct1304, 07:05 PM

P: 1,113

My friend asked for some help with derviatives, I said I would explain here then link him
Here is how you do it [tex] \frac {d}{dx} log_b(x) = \frac {1}{xlnb} [/tex] 



#2
Oct1304, 07:23 PM

P: 1,113

so you have at first
[tex] \frac {d}{dx} log_{10}(10/x) = \frac {1}{\frac{10}{x}ln10} [/tex] which simplifies to [tex] \frac {x}{10ln(10} [/tex] now you may think your done, but you need to remember the chain rule so you have [tex] \frac {x}{10ln(10} + \frac {d}{dx} \frac {10}{x}[/tex] so lets take the quotient rule and solve for [tex] \frac {10}{x}[/tex] f(x) = 10 f'(x)=0 g(x) = x g'(x)=1 g(x)f'(x)f(x)g'(x)  g(x)^2 x*010*1  x^2 = [tex] \frac {10}{x^2} [/tex] so then muliply [tex] \frac {x}{10ln(10)} * \frac {10}{x^2} [/tex] and you will get [tex]\frac {d}{dx} log_{10}(10/x)= \frac {1}{ln(10)*x} [/tex] 



#3
Oct1304, 07:27 PM

P: 1,113

Any other help you could probably use this website address
http://people.hofstra.edu/faculty/St...s/unit3_3.html 


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