Question

C=5坐标是(2,-3) 求椭圆公式 谢

Answer 1

设方程是x^2/a^2+y^2/b^2=1

a^2-b^2=c^2=25

4/a^2+9/b^2=1

4/a^2+9/(a^2-25)=1

4a^2-100+9a^2=a^4-25a^2

a^4-38a^2+100=0

解出a^2即可.