This right over here is du, and then this right over here is our u. And so this nicely simplifies to the integral of u to the 10th power, u to the 10th power, du. And so you would evaluate what this is, find the antiderivative here, and then you would back-substitute the natural log of x for u, and to actually evaluate this indefinite integral. Let's do another one. Let's say that we have the integral of, let's do something interesting here. Let's say the integral of tangent x, dx. Does u-substitution apply here?