What is the derivative of log(8x-1)?

1 Answer
Jul 30, 2015

8/(ln(10)(8x-1)) approx 3.474/(8x-1)

Explanation:

Assuming log(x)=log_{10}(x), d/dx(log(x))=1/(ln(10)x), where ln(10)=log_{e}(10) (and e approx 2.71828).

By the Chain Rule, d/dx(f(g(x)))=f'(g(x))*g'(x), we get

d/dx(log(8x-1))=1/(ln(10)(8x-1)) * d/dx(8x-1)

=8/(ln(10)(8x-1)) approx 3.474/(8x-1).