离心率 (x^2)/9-(y^2)/4 =1

解答

离心率

\frac{x ^{2}}{9} - \frac{y ^{2}}{4} = 1

\frac{13}{3}

十进制

1.20185 \dots

求解步骤

= \frac{a ^{2} + b ^{2}}{a}

计算双曲线性质

\frac{x ^{2}}{9} - \frac{y ^{2}}{4} = 1 :

左右开口双曲线，

(h, k) = (0, 0), a = 3, b = 2

= \frac{3 ^{2} + 2 ^{2}}{3}

整理后得

= \frac{13}{3}

ecce n t r i c i t y x^{2} - y^{2} = 25

ecce n t r i c i t y \frac{x ^{2}}{45} - \frac{y ^{2}}{216} = 1

ecce n t r i c i t y 16 x^{2} - 9 y^{2} - 64 x - 18 y + 199 = 0

ecce n t r i c i t y \frac{x ^{2}}{4} - \frac{y ^{2}}{16} = 1

ecce n t r i c i t y 49 x^{2} - 25 y^{2} - 686 x - 50 y + 2375 = 0