We use derivatives whilst moving a sine wave to the left to calculate the slope and using the inverse tangent function to calculate the angle and position of where the boat should be. The derivative of sin(x) is cos(x), so if we plug in x to cos(x) for the x value the boat is it we get the slope of the curve where the boat is at. We can use inverse tangent to find the angle, therefore making a cool effect of a boat rocking on waves.
