cos a +cos b etc.

Topic:Vectors 2D (Two-Dimensional), Addition, Angles, Calculus, Circle, Constructions, Coordinates, Cosine, Geometry, Mathematics, Median Line, Numbers, Ratios, Real Numbers, Reflection, Right Triangles, Sine, Subtraction, Geometric Transformations, Triangles, Trigonometric Functions, Trigonometry, Unit Circle, Vectors