This is a trig function and has the shape of sine or cosine. Since it intersects at (0,0), it is likely a sine graph. A normal sine graph starts at (0,0), crests up at 1, and crosses back down at the x-axis at (3.14, 0). However, this graph starts at (0,0) and crosses back again at half that value. This graph has been horizontally compressed by multiplication of a number greater than 1. So this graph is Sin 2x.
