But lucky for us, there is another property. And we went the other way when we were first taking derivatives of natural log functions. The antiderivative of one over x, or x to the negative one, is equal to, sometimes you'll see it written as natural log of x plus c. And sometimes, and I actually prefer this one because you could actually evaluate it for negative values, is to say the absolute value, the natural log of the absolute value of x. And this is useful because this is defined for negative values, not just positive values. The natural log of x is only defined for positive values of x. But when you take the absolute value, now it could be negative or positive values of x. And it works, the derivative of this is indeed one over x.