But let me just state the quotient rule right now. So if you have some function defined as some function in a numerator divided by some function in the denominator, we can say its derivative, and this is really just a restatement of the quotient rule, its derivative is going to be the derivative of the function in the numerator, so d dx f of x times the function in the denominator, so times g of x minus, minus the function in the numerator, minus f of x, not taking its derivative, times the derivative of the function in the denominator, d dx g of x, all of that over, so all of this is going to be over the function in the denominator squared. So this g of x squared, g of x, g of x squared. And you could use different types of notation here, you could say, instead of writing this with the derivative operator, you could say this is the same thing as g prime of x, and likewise, you could say, well, that is the same thing as f prime of x. And so now we just want to evaluate this thing, and you might say, well, how do I evaluate this thing? Well, let's just try it. Let's just say, well, we want to evaluate f prime when x is equal to negative one.