x∈[0,π],则x＋π/6∈[π/6,7π/6],因cos(x＋π/6)=3/5>0,则x＋π/6∈[0,π/2],所以sin(x＋π/6)=4/5,则sinx=sin[(x＋π/6)－π/6]=sin(x＋π/6)cos(π/6)－cos(x＋π/6)sin(π/6)=(4√3－3)/10.
