So for example, they would compute this, f prime of g prime of x. f prime of g prime of x. Which in this case, f prime of x is one over x, but if the input is g prime of x, g prime of x is cosine of x. So many students end up doing this, where they take the derivative of the outside and they apply, and the input into that, they use the derivative of the inside function. This, this is not right. Be very careful that you're not doing that. You do the derivative of the outside function with respect to the inside function, not taking its derivative, and then multiply, don't forget to multiply, times the derivative of the inside function here. So hopefully that helps a little bit.