So let's say that we are trying to take the derivative of the expression. So let's say we're taking the derivative of the expression, the natural log of sine of x. So the first key misconception or misunderstanding that many people have is when you're dealing with transcendental functions like this. And transcendental functions is just a fancy word for these functions like trigonometric functions, logarithmic functions that don't use standard algebraic operations. But when you see transcendental functions like this or compositions of them, many people confuse this with the product of functions. So at first when they look at this, they might see this as a product of functions. When they look at this, they might see this as being the same as the derivative with respect to x of natural log of x, natural log of x times sine of x.