有一类以角度θ为参数的问题,其式子中含有cosθ,sinθ,鉴于cosθ,sinθ与单位圆的关系,因此,解题时可以把问题转化为与定圆相关的曲线(直线族、圆族)问题,解题者要善于识破题目中曲线的“动”规律,作出定圆,让点在圆上动,以静制动,并采用数形结合的方法进行求解.下面就此类问题对其进行分类解析. There is a class of problems that take the angle θ as a parameter and the formula contains cos θ and sin θ. In view of the relationship between cos θ and sin θ and the unit circle, the problem can be transformed into the curve related to the fixed circle (straight line family, circle Family) problem, the problem-solver should be good at breaking the curve of the subject “move ” rule, make a round, so that the point in the circle move to static braking, and the use of numerical combination of the method to solve. Problem classification analysis.