What is, we know what v prime of x is, but what is v prime of u of x? Well, v prime of u of x, wherever we see the x, we replace it, let me write that a little bit neater, we replace that with a u of x. So v prime of u of x is going to be equal to, is going to be equal to one over u of x, one over u of x, u of x, which is equal to, which is equal to one over, u of x is just the square root of x, one over the square root of x. So this thing right over here, we have figured out is one over the square root of x, and this thing, u prime of x, we figured out is 1 1⁄2 times x to the negative 1 1⁄2, and x to the negative 1 1⁄2, I could rewrite that as 1 1⁄2 times one over x to the 1 1⁄2, which is the same thing as 1 1⁄2 times one over the square root of x, or I could write that as one over two square roots of x. So what is this thing going to be? Well, this is going to be equal to, in green, v prime of u of x is one over the square root of x times, times u prime of x is one over two times the square root of x. Now what is this going to be equal to?