Or one way to think about it is, the integral from 0 to 1 half of the top function is g of x, which is sine of pi x. So sine of pi x. But if we just evaluated this integral, let me just put a dx over here. If we just evaluated this, we would get the area of this entire region. But what we need to do is subtract out the area underneath the second, underneath f of x. We need to subtract out the area under that. So we just subtract from that f of x.