The chain rule is a rule we use to take the derivative of a composition of functions, and it has two forms. We use the chain rule on the left-hand side of the equation to find the derivative. Okay, just a few more steps, and we’ll have our formula! The next thing we want to do is treat y as a function of x, and take the derivative of each side of the equation with respect to x. Therefore, by the definition of logarithms and the fact that ln(x) is a logarithm with base e, we have that y = ln(x) is equivalent to e^y = x. The definition of logarithms states that y = log b (x) is equivalent to b y = x. Next, we use the definition of a logarithm to write y = ln(x) in logarithmic form. To find the derivative of ln(x), the first thing we do is let y = ln(x). However, it’s always useful to know where this formula comes from, so let’s take a look at the steps to actually find this derivative. The derivative of ln(x) is 1/x and is actually a well-known derivative that most put to memory.