第1个回答 2010-02-21
sinA2+cosB2=1
sinAcosB+cosAsinB=sin(A+B) sinAcosB+cosAsinB=sin(A-B)
cosAcosB-sinAsinB=cos(A+B) cosAcosB+sinAsinB=cos(A-B)
tanA+tanB/1-tanAtanB=tan(A+B) tanA-tanB/1-tanAtanB=tan(A-B)
sin2A=2sinAcosA
cos2A=cosA2-sinA2=2cosA2-1=1-2sinA2
tan2A=2tanA/1-tanA2
在斜三角形ABC中:tanA+tanB+tanC=tanAtanBtanC
几个三角恒等式:sinA+sinB=2sin(A+B/2)cos(A-B/2)
sin(A+B)+sin(A-B)=2sinAcosB
大概就这么多了