一、教学实录例过点P(4,2)的直线l分别与x轴的正半轴、y轴的正半轴交于点A、点B,求|PA|·|PB|的最小值.这是笔者在高三一轮复习“直线及其方程”中为学生准备的一道例题,主要考查直线的方程、两点间的距离公式、均值不等式等多个知识点,考查坐标法、数形结合思想、函数思想等多种数学思想方法.解决 First, the teaching of real cases past point P (4,2) of the line l, respectively, with the positive x-axis, the positive y-axis axis at point A, point B, find | PA | · | This is the author in the third year review “straight line and its equation ” for students prepared an example, the main test straight line equation, the distance between two points, mean inequality and other knowledge points, check the coordinate method , A few forms with thought, function thought and other mathematical methods