孤-独-草--
幼苗
共回答了23个问题采纳率：91.3% 举报
由sin^2 a=（1-cos 2a）/2可知
条件可化简为
[1-cos(2x+π/6)]/2 -[1-cos(2x-π/6)]/2 =1/4
cos(2x-π/6)-cos(2x+π/6)=1/2
cos2xcosπ/6+sin2xsinπ/6-(cos2xcosπ/6-sin2xsinπ/6)=1/2
2sin2xsinπ/6=1/2
sin2x=1/2
由x在（π/4,π/2）,
x=5π/12,
tanx=2+根号3
1年前
10
