题目

设角a=-35π/6°,则2sin(π＋α)cos(π-α)-cos(π+α)/1+sin^2α+sin(π-α)-cos^2(π+α)

提问时间：2020-10-12

答案

a=35π/6a=6π-π/6a=-π/62sin(π+a)cos(π-a)-cos(π+a)/[1+sin^2a+sin(π-a)-cos^2(π+a)]=2sin(π-π/6)cos(π+π/6)-cos(π-π/6)/[1+sin^2(-π/6)+sin(π+π/6)-cos^2(π-π/6)]=2sinπ/6(-cosπ/6)-(-cosπ/6...