And so we could just substitute pi in. And we just want to ensure that we don't get a zero in the denominator, because that would make it undefined. So we get sine of pi over cosine of pi, which is equal to zero over negative one, which is completely fine. If it was negative one over zero, we'd be in trouble. But this is just going to be equal to zero. So that works out. But if I were to ask you, what is the limit as x approaches pi over two of tangent of x?