f(x)=3 sin x+ln(5x)
f'(x) = 3 cosx + 1/x
Note that ln(5x) = ln5 + lnx
So, the ln5 is just a constant, with zero derivative
Of course, you could use the chain rule, so
d/dx ln(5x) = (1/5x)*5 = 5/5x = 1/x
If f(x)=3 sin x+ln(5x), find f '(x).
1 answer