已知椭圆x^2/4+y^2=1,过点M（2,3）引直线交椭圆于A,B两点,求弦AB的中点P的轨迹方程

P(x,y)xA+xB=2x,yA+yB=2yk(AB)=(yA-yB)/(xA-xB)=(yP-yM)/(xP-xM)=(y-3)/(x-2)x^2/4+y^2=1(xA)^2/4+(yA)^2=1.(1)(xA)^2/4+(yB)^2=1.(2)(1)-(2):(xA+xB)*(xA-xB)/4+(yA+yB)*(yA-yB)=0(xA+xB)+4(yA+yB)*(yA-yB)/(xA-xB)...