In a sailboat, the mast leans at an angle of theta with respect to the deck. An observer stainging on a dock watches the boat go by at speed v. Assume the boats is perpendicular to the observers line of sight and that its motion is also perpendicular to the observers line of sight. What angle does the observer observe the mast at. I got tan^-1( tan theta * gamma). However, that seems very wrong because I have never seen a tangent inside a tan^-1.