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. This is actually one of these key errors that the folks at the college board, the AP folks, told us about. Is that when dealing with these transcendental functions, cosine, sine, tangent, natural log, that are written like this, and people see the parentheses and then see another parentheses, their brain just says, oh, let me multiply these two expressions in parentheses. But that's not right, because if we were to add parentheses, this is what this is implying.