Question 24954
I'll make up a problem:
y = log (x^2+5)  base 3
This can be written as 
y = [ln(x^2+5)]/[ln 3]

Taking the derivative remember derivative of ln u is (1/u)du.
So, 
y' = (1/ln3)(1/(x^2+5)(2x) by the chain rule.

Cheers,
stan H.