You might be more familiar with seeing the derivative operator this way, but in theory, you won't see this as often, but this helps my brain really grok what we're doing. We're taking the derivative of cosine of x with respect to x, well that's gonna be negative sine of x. Well what about taking the derivative of cosine of x to the third power with respect to cosine of x? What does this thing over here mean? Well, if I was taking the derivative, if I was taking the derivative of, let me write it this way, if I was taking the derivative of x to the third power, x to the third power with respect to x, if it was like that, well this is just going to be, and let me put some brackets here to make it a little bit clearer. If I'm taking the derivative of that, that is going to be, that is going to be, we bring the exponent out front, it's going to be three, three times x, three times x to the second power. Three times x to the second power.