我们知道,经过点M_0(x_0,y_0),倾斜角为α(α≠π/2)的直线l的参数方程为{x=x_0+tcosα,y=y_0+tsinα(t为参数),其中参数t的几何意义是:|t|表示直线上的动点M(x,y)到定点M_0(x_0,y_0)的距离,若t>0,则动点M在定点M_0的上方;若t<0,则动点M在定点M_0的下方;若t=0,则动点M与 We know that the parameter equation of the straight line l passing through the point M_0 (x_0, y_0) and the inclination angle α (α ≠ π / 2) is {x = x_0 + tcosα, y = y_0 + tsinα (where t is a parameter) The geometric meaning of t is: | t | represents the distance between the moving point M (x, y) on the line and the fixed point M_0 (x_0, y_0), and if t> 0, the moving point M is above the fixed point M_0; if t < 0, the moving point M is below the fixed point M_0; if t = 0, then the moving point M and