So actually let me do it, color code it. So the derivative of this is two x plus five. So it should have been two x plus five, times the second thing, so times sine of x, times, let me do it in another color, times sine of x. And then to that, he would add the first thing, which is x squared plus five x, times the derivative of the second thing. So the derivative of sine of x is cosine of x. So this is what we should have been seeing at this step right over here. He shouldn't have just taken the product of the derivatives, he should have applied the product rule.