To determine the distance downwind of a turbine, we need to project the location vector (@, y) of the turbine onto the wind vector w. W sin 0 cos 0 (x, y) D If the wind is from direction 0 (measured clockwise from North), then the magnitude of the x and y components of the wind direction will be sin 0 and cos respectively. However, the wind is from direction 0, not towards direction 0, so the (unit length) wind vector will be (- sin , - cos ). The scalar projection (i.e. magnitude) of the location vector onto the wind vector is just the dot product of these two vectors, which is (-a sin 0, -y cos ). Implement the following function to compute this downwind distance