设角5π/6终边上一点为（m,n）,则m＜0 n＞0 m＝﹣√3n m²＋n²＝4n²∴sin5π/6＝n/√(m²＋n²)＝n/(2n)＝1/2cos5π/6＝m/√(m²＋n²)＝m/(2n)＝﹣√3/2tan5π/6＝n/m＝﹣√3/3cot5...