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e > 1

CON011 · Conic sections · Classes 11–12

Hyperbola eccentricity

For a hyperbola x²/a² − y²/b² = 1, c² = a² + b² and the eccentricity e = c/a is always greater than 1.

📐 Formula

e = c/a = √(1 + b²/a²)

✏️ Worked example

a = 3, b = 4: c = 5, e = 5/3 ≈ 1.67; asymptotes y = ±(4/3)x.

🌍 Where it is used

Navigation systems (LORAN) and some comet paths.

❓ Quick check

Eccentricity of a rectangular hyperbola (a = b)?

🏋️ Practice

Easya = 6, b = 8. e?

Answer: 5/3

MediumAsymptotes of x²/9 − y²/16 = 1?

Answer: y = ±4x/3

ChallengeCan a hyperbola have e = 0.9?

Answer: No