01sin(A+B)=sinAcosB+cosAsinB sin(A-B)=sinAcosB-cosAsinB? cos(A+B)=cosAcosB-sinAsinB cos(A-B)=cosAcosB+sinAsinB tan(A+B)=(tanA+tanB)/(1-tanAtanB) tan(A-B)=(tanA-tanB)/(1+tanAtanB) cot(A+B)=(cotAcotB-1)/(cotB+cotA)? cot(A-B)=(cotAcotB+1)/(cotB-cotA)
02
双曲函数 sinh(a)=(e^a-e^(-a))/2 cosh(a)=(e^a+e^(-a))/2 tgh(a)=sinh(a)/cosh(a)
03
和差化积 sin(a)+sin(b)=2sin[(a+b)/2]cos[(a-b)/2] sin(a)-sin(b)=2cos[(a+b)/2]sin[(a-b)/2] cos(a)+cos(b)=2cos[(a+b)/2]cos[(a-b)/2] cos(a)-cos(b)=-2sin[(a+b)/2]sin[(a-b)/2] tanA+tanB=sin(A+B)/cosAcosB
04
积化和差公式 sin(a)sin(b)=-1/2*[cos(a+b)-cos(a-b)] cos(a)cos(b)=1/2*[cos(a+b)+cos(a-b)] sin(a)cos(b)=1/2*[sin(a+b)+sin(a-b)]
正弦二倍角公式：sin2α = 2cosαsinα余弦二倍角公式：1.cos2A = 2cos²A-12.cos2A = 1−2sin²A3.cos2A = cos²A−sin²A正切二倍角公式tan2α = 2tanα/[1 - (tanα)²]
