It becomes positive sine of t. So the antiderivative of sine of t is negative cosine of t. So this is going to be equal to negative cosine of t. And then what's the antiderivative of cosine of t? Well, we already know that the derivative with respect to t of sine of t is equal to cosine of t. So cosine of t's antiderivative is just sine of t. So plus sine of t. And we're done. We found the antiderivative. Now let's tackle this. Now we don't have a t. We're taking the indefinite integral with respect to, actually, this is a mistake. This should be with respect to a. Let me clean this up.