Parametric Curves Explorer

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

Parametric Curve

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2

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, 2ฯ€]
  • Each value of t gives a point (x, y) on the curve
  • Lissajous: the ratio a : b determines the shape โ€” 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) โ€” frequency ratio a:b determines pattern
  • Epicycloid: circle of radius b rolling outside a circle of radius a โ€” produces cusps
  • Astroid: special epicycloid with 4 cusps, x = aยทcosยณt
  • Butterfly: r = ecos t โˆ’ 2cos(4t) + sin&sup5;(t/12) in polar form
  • Hypotrochoid: circle rolling inside another โ€” the Spirograph principle