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旋转变换是几何图形中的重要变换方法,利用旋转法解决有关计算或证明问题,往往能迅速找到解题的突破口,使问题简单化.本文通过几例来体会利用旋转法解题的巧妙.例1已知,如图1,等腰△ABC中,AB=AC,P为△ABC内一点,已知∠APB=∠APC,试说明BP=CP.解析本题看似简单,但细细分析,难以利用全等的条件得到两线段相等,需要我们另辟蹊径.将△ABP绕A点按逆时针旋转,使得AB与AC重合,则△ABP旋转后得到△ACP’.于是,
Rotation transformation is an important transformation method in geometry, the use of rotation method to solve the problem of calculation or proof, often can quickly find a breakthrough in solving problems, to simplify the problem.Through several examples to understand the use of rotation method to solve the ingenious. 1 known, as shown in Figure 1, isosceles △ ABC, AB = AC, P is a point △ △, known ∠ APB = ∠ APC, try to explain BP = CP. Analysis of this problem may seem simple, It is difficult to use the congruent condition to get the two line segments equal, which requires us to find a new way.A △ ABP is rotated anticlockwise around point A, so that AB and AC coincide, then △ ABP rotates to get △ ACP ’