|
椭圆x^2/6+y^2/2=1右焦点（2,0)园N:x^2+(y-2)^2=1由圆的参数方程设点E(2+cosα.sinα),F(2-cosα,-sinα)P(x,y),y^2=2-x^2/3,x∈[-√6,√6]u=向量PE点乘向量PF=(2+cosα-x,sinα-y)*(2-cosα-x,-sinα-y)=(2+cosα-x)(2-cosα-x)+(sinα-y)(-sinα-y)= (2-x)^2-cos2ā+y^2-sin2α =(2-x)^2+y^2-1= x^2-4x+5-x^2/3=2/3 *x^2 -4x +5 =2/3(x-3)^2-1∴x=3,... |
