So, this is the same thing as cosine of two pi or the same thing as cosine of zero. So that is going to be equal to one. If that seems unfamiliar to you, I encourage you to review the unit circle definition of cosine. And what is cosine of 11 pi over two? Let's see, let's subtract some, let's subtract some multiple of two pi here to put it in values that we can understand better. So this is, so let me write it here. Cosine of 11 pi over two.