重点难点易混易错点剖析复习重点:圆的概念,垂径定理,圆周角定理,直线与圆的位置关系,扇形和弧长的概念与计算.复习难点:利用垂径定理和圆周角定理进行证明和计算,在圆中作出相应的辅助线,判断直线与圆的位置关系,切线的性质与识别,计算阴影部分的面积.易混易错点:在应用垂径定理、切线性质与识别时往往要添加辅助线实现思路贯通,添 Key Points Difficult Points Easy to Analyze Error Points Review Points: Circle Concept, Diameter Theorem, Circle Angle Theorem, Position Relationship between Line and Circle, Concept and Calculation of Sector and Arc Length Difficulties in Difficulties: Using the Diagonal Theorem and Circular Angle Theorem Prove and calculate, make the corresponding auxiliary line in the circle, judge the relationship between the position of the line and the circle, the nature and recognition of the tangent and calculate the area of ​​the shaded part. When often to add auxiliary line to achieve ideas through