文档介绍：(-a)=-sin(a)cos(-a)=cos(a)sin(π/2(90度)-a)=cos(a)cos(π/2(90度)-a)=sin(a)sin(π/2(90度)+a)=cos(a)cos(π/2(90度)+a)=-sin(a)sin(π(180度)-a)=sin(a)cos(π(180度)-a)=-cos(a)sin(π(180度)+a)=-sin(a)cos(π(180度)+a)=-cos(a)(a+b)=sin(a)cos(b)+cos(α)sin(b)cos(a+b)=cos(a)cos(b)-sin(a)sin(b)sin(a-b)=sin(a)cos(b)-cos(a)sin(b)cos(a-b)=cos(a)cos(b)+sin(a)sin(b)tan(a+b)=[tan(a)+tan(b)]/[1-tan(a)tan(b)]tan(a-b)=[tan(a)-tan(b)]/[1+tan(a)tan(b)](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](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)](2a)=2sin(a)cos(b)cos(2a)=cos2(a)-sin2(a)=2cos2(a)-1=1-2sin2(a)(a/2)=[1-cos(a)]/2cos2(a/2)=[1+cos(a)]/2tan(a/2)=[1-cos(a)]/sin(a)=sina/[1+cos(a)](a)=2tan(a/2)/[1+tan2(a/2)]cos(a)=[1-tan2(a/2)]/[1+tan2(a/2)]tan(a)=2tan(a/2)/[1-tan2(a/2): cos(arcsinx)=√(1-x^2) arcsin(-x)=-arcsinx os(-x)=π-osx arctan(-x)=-arctanx ot(-x)=π-otx arcsinx+osx=π/2=arctanx+otx sin(arcsinx)=cos(osx)=tan(arctanx)=cot(otx)