1. The problem statement, all variables and given/known data Imagine a life guard situated a distance d1 from the water. He sees a swimmer in distress a distance L to his left and distance d2 from the shore. Given that his speed on land and water are v1 and v2 respectively, with v1 > v2, what trajectory should he choose to get to the swimmer in the least time? Pick some trajectory composed of two straight line segments in each medium (why?) and give a relation for the angles of the two segments with respect to the normal to the shoreline. 2. Relevant equations Ha 3. The attempt at a solution Should I include the diffraction of water, or should I not because this is a human? I'm assuming that I should use diffraction of water and so the corresponding optics equations because of the implication by "..some trajectory composed of two straight lines in each medium". If I didn't include diffraction, the angle wouldn't change, it would just be a straight line all the way through?