cos(A-B)=cosAcosB+sinAsinB geometrical proof (video) Oct 1, 2017 21:17:58 GMT Quote Select PostDeselect PostLink to PostMemberGive GiftBack to Top Post by Tiago on Oct 1, 2017 21:17:58 GMT See how cos(A-B)=cosAcosB+sinAsinB can be derived geometrically by watching the video below. Feel free to drop comments, feedback and questions.