设M(x,y) P(a,b)则y/b=2/3 so b^2=9/4y^2
4-y/4-a=2/3 so a^2=9/4x^2-6x+9/4y^2=4
so 9x^2+9y-24x=0配方得(x-4/3)^2+y^2=16/9
so 选D
P是圆x^2+y^2=4上一动点,Q(4,0)为定点,若点M分PQ的比为1:2,则点M的轨迹方程是
P是圆x^2+y^2=4上一动点,Q(4,0)为定点,若点M分PQ的比为1:2,则点M的轨迹方程是
A.(x-2)^2+y^2=1
B.(x-8/3)^2+y^2=4
C.(x+4)^2+y^2=16
D.(x-4/3)^2+y^2=16/9
A.(x-2)^2+y^2=1
B.(x-8/3)^2+y^2=4
C.(x+4)^2+y^2=16
D.(x-4/3)^2+y^2=16/9
数学人气:319 ℃时间:2020-05-14 06:15:29
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