(sin13°+cos15°sin2°)/(cos13°-sin15°sin2°)
=[sin(15-2)+cos15°sin2°]/[cos(15-2)-sin15°sin2°]
=(sin15cos2)/(cos15cos2)
=sin15/cos15
=sin15cos15/(cos^2 15)
=sin30/(1+cos30)
=1/2/(1+√3/2)
=1/(2+√3)
=2-√3