The derivative of secant with respect to u of x, well instead of seeing an x everywhere, you're gonna see a u of x everywhere. So this is going to be sine of u of x, sine of u of x, u of x, and I could, I don't have to write u of x, I could write three pi over two minus x, but I'll write u of x right over here just to really visualize what we're doing. So sine of u of x over, over cosine squared of u of x. Cosine squared, let me do those parentheses in the blue color just to make sure that you identify it with the trig function. So cosine squared of u of x, u of x. So that's the derivative of secant with respect to u of x, and then the chain rule tells us it's gonna be that times u prime, u prime of x. So what is this going to be equal to? Well, I could just substitute back.