So let's multiply the numerator and the denominator here by g of x so that we have everything in the form of g of x squared in the denominator. So if we multiply the numerator by g of x, we'll get g of x right over here. And then the denominator will be g of x squared. And now we're ready to add. And so we get the derivative of f of x over g of x is equal to the derivative of f of x times g of x minus, not plus anymore, minus, let me write it in white, minus f of x times g prime of x. Times g prime of x, all of that over g of x squared. So once again, you can always derive this from the product rule and the chain rule.