Question

Differentiate (ln(f+g))

Answer 1

This should now be easy for you, if you found the derivative of ln(fg).

For the record
\[ \frac{d \ }{dx} ln (f) = \frac{f'}{f} \]

Answer 2

I understand ln(fg) = f'/f+g'/g, but what differently do I do here?

Answer 3

so d/dx ln(u) = u'/u.

Write here u = f + g.

Then d/dx ln(u) = .... what?

Answer 4

d/dx ln(u) = u'/u = ....

Answer 5

f+g/f'+g'?

Answer 6

careful

Answer 7

Ooops lol. f'+g'/f+g

Answer 8

d/dx ln(u) = u'/u = (f + g)' / (f + g) = ....

Answer 9

yes

Answer 10

Thanks a bunch. You officially have what I like to call Swag.

Answer 11

Much obliged ;-)