cos10°/sin50°*(tan10°-√3)=cos10°(tan10°-√3)/sin50°=(sin10°-√3cos10°)/sin50°=2(sin10°/2-√3cos10°/2)/sin50°=2(sin10°cos60°-cos10°sin60°)/sin50°=2(sin(10°-60°)/sin50°=-2sin50°/si...