古人说,动静相生.有一类以角度θ为参数的问题,其条件中含有关于cosθ,sinθ的式子,鉴于cosθ,sinθ与单位圆的关系,求解时可以转化为与定圆相关的曲线(直线族、圆族)问题.解题者要善于把握题目中曲线“动中有静”的规律,作出定圆,让点在圆上运动,以静制动,并采用数形结合的方法探究.下面就此类问题进行分类解析. According to the ancients, there is a kind of problem that takes the angle θ as a parameter, and the condition contains the formula about cosθ, sinθ. In view of the relationship between cosθ, sinθ and unit circle, the solution can be transformed into the curve related to the fixed circle Straight line family, round family) problem.The problem-solving person should be good at grasping the theme of the curve “movement in the static ” law, make a round, let the point on the circle movement, to static braking, and the combination of number Approach to explore. Below the classification of such issues.