Question

Hi,
Can you help me find the derivative of f(x)=2ln(7x)?

Thanks.

Answer 1

y=2ln(7x)
and you need dy/dx.

Answer 2

the derivative of y, is dy/dx.
the derivative of ln(7x) is by the chain rule,
the inner argument "7x" is going to be over one, like this : 1/(7x)
and times the derivative of the inner function, times the derivative of "7x" (which is 7)

So

d/dx 2 ln (7x) = 2 (1 / 7x ) (7) = 14 / (7x) = 2/x


So,

dy/dx = 2/x

Answer 3

Wow, this is very clear. Thank you!