Sum and difference formula sin (a+b) = sinacosb+Cosasin (a-b) = sinacosb-sinbcosa? cos(A+B)= cosa cosb-Sina sinb cos(A-B)= cosa cosb+Sina sinb tan(A+B)=(tanA+tanB)/( 1-tanA tanB)tan(A-B)=(tanA-tanB)/( 1+tanA tanB)？

Introduction to mathematics:

Mathematics (hanyu pinyin: shùXué；; ; Greek: μ α θ η μ α κ; English: Mathematics comes from the ancient Greek word μ θ η μ α (má th?ma), which means learning, learning and science. Ancient Greek scholars regarded it as the starting point of philosophy and the "foundation of learning". In addition, there is a narrow and technical meaning-"mathematical research". Even in its etymology, its adjective meaning related to learning will be used to refer to mathematics.

Its plural form in English and as the plural form of mathématiques in French +es can be traced back to the Latin neutral plural (Mathematica), which is Cicero's plural from Greek τ α α θ ι α τ κ? (ta mathē matiká). In ancient China, mathematics was called arithmetic, also called arithmetic, and finally changed to mathematics. Arithmetic in ancient China was one of the six arts (called "number" in the six arts).