(sin6+cos15*sin9)/(cos6-sin15*sin9)
=[sin(15-9)+cos15*sin9]/[cos(15-9)-sin15sin9]
=(sin15cos9-cos15sin9+cos15sin9)/(cos15cos9+sin15sin9-sin15sin9)
=(sin15cos9)/(cos15cos9)
=sin15/cos15
=tan15
=(1-cos30)/sin30
=2-√3
(sin6+cos15*sin9)/(cos6-sin15*sin9)
=[sin(15-9)+cos15*sin9]/[cos(15-9)-sin15sin9]
=(sin15cos9-cos15sin9+cos15sin9)/(cos15cos9+sin15sin9-sin15sin9)
=(sin15cos9)/(cos15cos9)
=sin15/cos15
=tan15
=(1-cos30)/sin30
=2-√3