Parametric Curves Explorer

Plot Lissajous figures, epicycloids, astroids, butterfly curves, and hypotrochoids. Watch the curve trace as the parameter t sweeps from 0 to 2π.

Parametric Curve

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Properties

Curve--
x(t)--
y(t)--
Period--
Symmetry--

The Math Behind It

Parametric Equations

  • A curve is defined by separate functions x(t) and y(t)
  • The parameter t usually ranges over [0, 2π]
  • Each value of t gives a point (x, y) on the curve
  • Lissajous: the ratio a : b determines the shape — rational ratios close the curve
  • Parametric form lets us describe curves that fail the vertical line test

Famous Curves

  • Lissajous: x = sin(at), y = sin(bt) — frequency ratio a:b determines pattern
  • Epicycloid: circle of radius b rolling outside a circle of radius a — produces cusps
  • Astroid: special epicycloid with 4 cusps, x = a·cos³t
  • Butterfly: r = ecos t − 2cos(4t) + sin&sup5;(t/12) in polar form
  • Hypotrochoid: circle rolling inside another — the Spirograph principle