And then you wanna multiply that times the derivative of the inside with respect to x. So the derivative of seven x squared is 14 x. Derivative of four x is four. So this is actually, that step looks good. But then Nejoman does something strange over here. This is the cosine of seven x squared plus four x, and then that whole thing times 14 x plus four. But they get confused where, just looking at these parentheses, and this tends to happen sometimes.