（tan10°-√3）×cos10°/sin50° =（sin10°/cos10°-√3）×cos10°/sin50° =（sin10°-√3cos10°）/sin50° =2（1/2×sin10°-√3/2×cos10°）/sin50° =2（cos60°sin10°-sin60°cos10°）/sin50° =2×sin...