So for example, if we call this right over here u of x. So let's do that. So if we say u of x is equal to three pi over two minus x, we could also figure out u prime of x is going to be equal to derivative of three pi over two, that's just going to be zero, derivative of minus x, so that's just going to be minus one, and you could just view that as a power rule. It's one times negative one times x to the zero power, which is just one. So there you go. So we could view this as the derivative of secant with respect to u of x, and when we take the derivative, the derivative of secant with respect to u of x times the derivative of u with respect to x. And you might say, well what about the derivative of secant?