【急】推导诱导公式 cos(π/2+α)=-sinα tan(π/2+α)=-cotα cot(π/2+α)=-tan
问题描述:
【急】推导诱导公式 cos(π/2+α)=-sinα tan(π/2+α)=-cotα cot(π/2+α)=-tan
答
cos(π/2+α)=-sinα ,tan(π/2+α)=-cotα,cot(π/2+α)=-tan诱导公式.推导过程如下:sin(π/2+α)= cos αsin(π+α) =sin[π/2+(π/2+α)]= cos(π/2+α)又sin(π+α) = - cosα) 所以:cos(...