Question

三角函数之间如何相互转换啊

三角函数之间如何相互转换啊

Answer 1

sin^2A+cos^2A=1
sinA/cosA=tanA
cosA/sinA=cotA
sin2A=2sinAcosA
cos2A=cos^2A-sin^2A=1-2sin^2A=2cos^2A-1
tan2A=2tanA/1-tan^2A
1+tan^2A=sec^2A=1/cos^2A
1+cot^2A=csc^2A=1/sin^2A
tanA * cotA=1
sinA*scsA=1
cosA*secA=1
sin(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-tan^2A)
tan(A-B)=(tanA-tanB)/(1+tan^2A)