If this was a natural log, well then this would be one over natural log of e times x, natural log of e is just one, so that's where you get the one over x, but if you have any other base, you put the natural log of that base right over here in the denominator. So what is f prime of two? F prime of two is one over the natural log of 10 times two. So this whole thing has simplified, this whole thing is equal to five times this business. So I could actually just write it as, it's equal to five over, five over the natural log of 10, natural log of 10 times two. I could have written it as two natural log of 10s. The key here for this type of exercise, you might be like, oh let me see if I can evaluate this limit, but you're like, well, this looks a lot like the derivative of a logarithmic function, especially the derivative when x is equal to two, if we could just factor these fives out.