单位圆与三角函数线具有直观、简捷、准确、方便的特点,对于解决三角函数中一些求值、求范围、比较大小及证明题可以化难为易、思路清晰,效果颇好,是一种重要的手段.一、确定角的范围例1若sinx>1/2,求x的取值范围.解如图1,作单位圆,并作直线y=1/2与单位圆交于A、B两点,连结OA、OB,当α终边落在图 Unit circle and trigonometric line with intuitive, simple, accurate and convenient features, to solve some trigonometric functions in the evaluation, the scope, size and proof of the problem can be difficult to change, clear thinking, the effect is quite good, is an important First, determine the scope of the angle Example 1 If sinx> 1/2, find the value of x. Solution shown in Figure 1, as a unit circle, and make a straight line y = 1/2 and the unit circle at A, B Two o’clock, link OA, OB, when α final edge in the map