Here we would want to apply the product rule. This is going to be equal to, this is going to be equal to the derivative of the first function times the second function, plus the derivative, well let me write it this way, plus the first function, not taking its derivative, times the derivative of the second function. So he should have applied the product rule here. And so let's do that, just to see what his answer should have been. So what he should have done here, I'll get my correcting red pen out here, say no, that's not what he should have done. He says let's take the derivative of this first thing. So actually let me do it, color code it.