几何中的动态探究题是近年开放类试题的热点题型.解这类题时要切实把握几何图形在运动过程中的特殊位置,在“动”中求“静”,在“静”中探求“动”的一般规律.下面举几例谈谈动态探究题中定值问题结论的猜想与证明.例1已知,M是等腰三角形底边BC上的一动点,过M作AB,AC的平行线交 The dynamic inquiry question in geometry is a hot topic question in the open examination questions in recent years. When solving such questions, we must really grasp the special position of the geometric figure in the movement process, and seek “quietness” in “movement”, and seek in “static”. The general law of “movement”. Here are a few examples to talk about the conjecture and proof of the conclusion of the fixed value problem in dynamic inquiry questions. Example 1 It is known that M is a moving point on the base of the isosceles triangle BC. M over AB, AC Parallel lines