Cosine (cos) phonetic symbol is: ksa? N, Chinese transliteration: Quincy

Tangent (tan) phonetic symbol is:' t? Ndnt, Chinese transliteration: Tan Jingte, can also be pronounced as "Tan Ting"

Cot phonetic symbol is: k? t？ Ndnt, Chinese transliteration: Kutanjingte, which can also be pronounced as Kutanting.

The sum formula of two angles:

sin(A+B)= Sina cosb+cosa sinb sin(A-B)= Sina cosb-sinb cosa

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)

cot(A+B)=(cotA cotB- 1)/(cot B+cotA)cot(A-B)=(cotA cotB+ 1)/(cot B-cotA)