三角函数公式

两角和公式

sin(A B)=sinAcosB cosAsinB sin(A-B)=sinAcosB-sinBcosA

cos(A B)=cosAcosB-sinAsinB cos(A-B)=cosAcosB sinAsinB

tan(A B)=(tanA tanB)/(1-tanAtanB) tan(A-B)=(tanA-tanB)/(1 tanAtanB)

ctg(A B)=(ctgActgB-1)/(ctgB ctgA) ctg(A-B)=(ctgActgB 1)/(ctgB-ctgA)

倍角公式

tan2A=2tanA/(1-tan2A) ctg2A=(ctg2A-1)/2ctga

cos2a=cos2a-sin2a=2cos2a-1=1-2sin2a