sin(50°)*(-cos(35°))+sin(40°)*sin(35°) = -0.25881904510252
原式 = -sin50°cos35°+cos50°sin35°=sin(35°-50°)=sin(45°-60°)=sin45°cos60° - cos45°sin60°=√2/2*√3/2-√2/2*1/2=(√6-√2)/4
