离心率 (x^2}{49}-\frac{y^2)/4 =1

解答

离心率

\frac{x ^{2}}{49} - \frac{y ^{2}}{4} = 1

\frac{53}{7}

十进制

1.04001 \dots

求解步骤

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

计算双曲线性质

\frac{x ^{2}}{49} - \frac{y ^{2}}{4} = 1 :

左右开口双曲线，

(h, k) = (0, 0), a = 7, b = 2

= \frac{7 ^{2} + 2 ^{2}}{7}

整理后得

= \frac{53}{7}

ecce n t r i c i t y 9 \cdot x^{2} - 9 \cdot y^{2} = 9

ecce n t r i c i t y 9 x^{2} - 4 y^{2} - 90 x - 32 y = - 305

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

ecce n t r i c i t y \frac{x ^{2}}{27} - \frac{y ^{2}}{72} = 1

ecce n t r i c i t y \frac{x ^{2}}{36} - \frac{y ^{2}}{9} = 1