How do you differentiate log_xe?

1 Answer
Sep 11, 2016

= - 1/ (x ln^2 x)

Explanation:

you can use a base switch (see below for how it works), switching everything into base e
we have

y = log_x e

= (ln e)/(ln x) = 1/(ln x)

so y' = - 1/ (ln^2 x) * 1/x

= - 1/ (x ln^2 x)

Base Switching

let y = log_a b

implies a^y = b

We'll switch to base Q

So log_Q a^y = log_Q b

y log_Q a = log_Q b

y = (log_Q b)/(log_Q a )