So it's my y-axis, my x-axis, and then I have the unit circle. So, whoops, all right, the unit circle, just like that. So if we start at, this is zero, then you go to pi over two, then you go to pi, then you go to three pi over two. So that's this point on the unit circle. So the cosine is the x-coordinate, so this is going to be zero. This is zero, so this is zero. And so we get one minus zero, so everything in the brackets evaluates out to one.