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在高中数学立体几何、代数、解析几何中都有这类问题:存在性问题。题意是这样的:问是否存在这样的点、参数或直线,使得成立。这类题的解题思路是先假设这样的点、参数、直线存在,把结论当作条件结合已知进行合理的推理、证明、求解,若出现矛盾则假设不成立,这样的点、参数或直线不存在,若不出现矛盾则存在这样的点、参数或直线。这种题型处理方法固定,学生一般会动手,可是近几年高考题的客观题中也常出现一些“存在性”问题,它们如
In high school mathematics stereo geometry, algebra, analytic geometry, there are such problems: existence problems. The idea is this: Ask if there is such a point, parameter, or straight line that makes it true. The problem-solving idea of such questions is to first assume that such points, parameters, and straight lines exist, and use the conclusions as conditions in conjunction with known reasonable reasoning, proof, and solution. If there are contradictions, the assumptions do not hold, such points, parameters, or straight lines. Does not exist, if there is no contradiction there is such a point, parameter or straight line. This question-type processing method is fixed, students generally will start hands, but in recent years the subject of the college entrance examination questions also often appear some “existence ” problems, such as