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Hyperbola Calculator

Find a hyperbola's foci distance, eccentricity, asymptote slope, and semi-latus rectum from its semi-transverse and semi-conjugate axis lengths.

Distance from center to each focus (c)
5
Eccentricity (e = c/a)
1.6667
Asymptote slope (±b/a)
±1.3333
Semi-latus rectum (b²/a)
5.3333

How it works

For a hyperbola in standard position, x²/a² − y²/b² = 1, a is the semi-transverse axis (half the distance between the two vertices) and b is the semi-conjugate axis (half the distance between the co-vertices, which fix the curve's asymptotes but don't themselves lie on it). The distance from the center to each focus is c = √(a² + b²) — note the plus sign, the opposite of an ellipse's c² = a² − b², because a hyperbola's foci sit further out than its vertices rather than closer in.

Eccentricity, e = c/a, is always greater than 1 for a hyperbola (an ellipse's is always below 1, and a parabola's is exactly 1) — a larger e describes a 'wider,' flatter curve. The two asymptotes, the straight lines y = ±(b/a)x that the curve approaches but never touches, have slope exactly b/a. The semi-latus rectum, b²/a, is half the length of the chord that passes through a focus perpendicular to the transverse axis, a standard measure of how wide the curve is right at the focus.

Both axis lengths are treated as plain, unit-agnostic numbers — the same as this site's circle, ellipse, and triangle calculators — so the results come out in whatever unit the two axes were entered in.

FAQ

How is this different from the ellipse calculator?

An ellipse is a closed curve with c² = a² − b² and eccentricity strictly between 0 and 1; a hyperbola is two open, mirror-image branches with c² = a² + b² and eccentricity strictly greater than 1. They're both conic sections described by similar-looking equations, but they're geometrically very different shapes with different formulas for almost everything except the axis-length inputs themselves.

What do the asymptotes actually mean?

They're the two straight lines the hyperbola's branches get arbitrarily close to, but never reach, as you move away from the center. Their slope, ±b/a, depends only on the ratio of the two axis lengths, not on their absolute size — a hyperbola with a larger b relative to a opens up 'wider' and its asymptotes are steeper.

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