2、(x,y)---->(-y,-x);变换矩阵是(0,-1;-1,0);1、设(x,y)关于直线L的对称点位(x',y'),(y'-y)/(x'-x)*tgα=-1; (1) 直线L的方程为y=tgα*x,两个点到该直线的距离相等,即|y-tgα*x|/根号(1+tgα^2)=|y'-tgα*x'|/根号(1+tgα^2)------>(x,y)与(x',y')互异,y+y'=tgα*(x+x');(2)联立方程(1)、(2),x'=sec(2α)*x-tg(2α)*y,y'=tg(2α)*x-sec(2α)*y;坐标变换矩阵是(sec2α,-tg2α;tg2α,-sec2α)。... |