设椭返数圆方程为x^2/a^2+y^2/b^2=1因为焦点在x轴上,所以a>b>0PF1 F1F2 PF2成等差数列,则2F1F2=PF1+PF2又知PF1+PF2=2a所以F1F2=a又知焦距为2c=F1F2,所以c=a/2c^2=a^2-b^2得出b^2=a^2-a^2/4=3/4 a^2代入椭圆方程得,x^2/a^2+y^2/(3/4a^2)=1把点(2,√3)代入方程,得a^2=8,则b^2=6所以椭圆方程派晌:漏羡首x^2/8+y^2/6=1
F3是啥