早教吧作业答案频道 -->数学-->
(1+sina)/(1-2sin2a/2)求证(1+sina)/(1-2sin^2a/2)=(1+tana/2)/(1-tana/2)
题目详情
(1+sina)/(1-2sin2 a/2)
求证(1+sina)/(1-2sin^2 a/2)=(1+tan a/2)/(1-tan a/2)
求证(1+sina)/(1-2sin^2 a/2)=(1+tan a/2)/(1-tan a/2)
▼优质解答
答案和解析
(1+sina)/(1-2sin?a/2)=[sin?(a/2)+cos?(a/2)+2sin(a/2)cos(a/2)] / [cos?(a/2)-sin?(a/2)]
=[sin(a/2)+cos(a/2)]?/ [cos?(a/2)-sin?(a/2)]
=[sin(a/2)+cos(a/2)] / [cos(a/2)-sin(a/2)] ----------分子分母同除以cos(a/2)
=(1+tan a/2)/(1-tan a/2)
=[sin(a/2)+cos(a/2)]?/ [cos?(a/2)-sin?(a/2)]
=[sin(a/2)+cos(a/2)] / [cos(a/2)-sin(a/2)] ----------分子分母同除以cos(a/2)
=(1+tan a/2)/(1-tan a/2)
看了(1+sina)/(1-2si...的网友还看了以下：