(√3-tan10°)/sec50°=(√3-sin10°/cos10°)*cos50°=cos50°(√3cos10°-sin10°)/cos10°=2cos50°[cos10°*(√3/2)-sin10°*(1/2)]/cos10°=2cos50°(sin60°cos10°-cos60°sin10°)/cos10°=2cos50°sin50°/...