作业帮帮帮我!化简sin4a/(1+cos4a)*cos2a/(1+cos2a)*cosa/(1+cosa)*cos(a/2)/(1+cos(a/2))的过程
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/06 11:56:30
帮帮我!化简sin4a/(1+cos4a)*cos2a/(1+cos2a)*cosa/(1+cosa)*cos(a/2)/(1+cos(a/2))的过程
sin4a/(1+cos4a)*cos2a/(1+cos2a)*cosa/(1+cosa)*cos(a/2)/(1+cos(a/2))=
2sin2a*cos2a/(2cos2acos2a)*cos2a/(1+cos2a)*cosa/(1+cosa)*cos(a/2)/(1+cos(a/2))=sin2a/(1+cos2a)*cosa/(1+cosa)*cos(a/2)/(1+cos(a/2))=
以同法化简
=sin(a/2)/(1+cos(a/2))=tan(a/4)