数学`
直线l:3x+4y-1=0..L1:2x+y-4=0.直线L2与L1关于L对称`.求L2的方程`要求用两种方法`麻烦帮忙做做`.我先给20分了`做得好+分`谢谢`
L1的斜率k1 = -2 L的斜率 k = -3/4 L2的斜率k2 (k2 -k)/(1-k2k) =(k-k1)/(1-kk1) ===>k2 = -2/11 L1,L交点(3,-2) ==>L2: y =-2/11 (x-3)-2 ===>2x+11y+16=0 2)设L1上点(x0,y0)和L2点(x,y)关于L对称 则连线的中点在对称轴上 3[(x0+x)/2]+4[(y0+y)/2]-1 =0 =====> 3x0+4y0+3x+4y=2 又2x0+y0 =4 ==>2x+11y+16=0
答:解:1: 联立3X+4Y-1=0, 2X+Y-4=0求出两直线交点B的坐标 Xb=3 Yb=-2 ∴B(3,-2) 设L1上点A(2,0)...详情>>
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