:点A(11.2)到直线Y=(K+1)X+K-2的距离的取值范围是_______.
问题描述:
:点A(11.2)到直线Y=(K+1)X+K-2的距离的取值范围是_______.
答
因为d=[11(K+1)+K-2-2]/√[(K+1)^2+1]所以d√[(K+1)^2+1]=12K+7两边平方得d^2(K^2+2K+2)=144K^2+168K+49所以(d^2-144)K^2+(2d^2-168)K+2d^2-49=0所以由(2d^2-168)^2-4(d^2-144)(2d^2-49)≥0可得4d^4-672d^...