问题:在平面直角坐标系中,已知点P(x_0,y_0),直线l:Ax+By+C=0(A~2+B~2≠0),怎样由点的坐标和直线方程直接求点P到直线l的距离呢?思路1:如图1,过P作PQ⊥l,垂足为点Q,则垂线段PQ的长就是点P到直线l的距离,直线PQ的斜率为B/A(A≠0)。根据点斜式写出直线PQ的方程,与已知 Problem: In the Cartesian coordinate system, the point P (x_0, y_0) and the straight line l: Ax + By + C = 0 (A ~ 2 + B ~ 2 ≠ 0) Seeking point P to the distance of line l idea 1: As shown in Figure 1, P for PQ⊥l, foot for the point Q, then the vertical line segment PQ is the length of the point P to the straight line l distance, the slope of the straight line PQ B / A (A ≠ 0). The equation for the straight line PQ is written obliquely according to the point, and is known