原题目　老鼠离开洞穴沿直线前进,它的速度与到洞穴的距离成反比,当行进到离洞口为a的甲处时速度为va,求老鼠从甲处运动到距离洞口为b的乙处所用的时间。解法1　微元叠加法如图1所示,将甲乙之距(b-a)等分为n份,(n∞),每份为x=b-an,(x0),则老鼠在每一份内做匀速运动,第一段 The original title mouse left the cave along the straight line, its speed is inversely proportional to the distance to the cave, when going to a from the hole at the mouth of the speed of va, ask the mouse to move from a place to the distance from the hole for the b place B time. Solution 1 The microelement superposition method is shown in Fig. 1. The distance between A and B (ba) is equally divided into n parts, (n∞), each of which is x=b-an, (x0). One uniform motion within the first paragraph