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. So you can't just take the 14 x plus four and multiply it by this, and assuming you're taking the cosine of the whole thing. So this is where Nejoman makes the mistake. The work is not correct, and the mistake is trying to multiply these two expressions and taking the cosine of the whole thing.