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Parametric Curve Plotter

Plot parametric equations x(t) and y(t) with animated trace, adjustable parameter ranges, and multiple curve overlay.

Tested tool guide Tested browser tools Checked August 16, 2026

What Parametric Curve Plotter does, with a checked example

This tool draws the curve traced by two independent expressions, x(t) and y(t), evaluated together as t sweeps across a range you set, then connects the resulting points and can animate a marker moving along them. Because the curve is defined by a shared parameter rather than y as a function of x, it can draw loops, cusps, and self-crossing paths no single y=f(x) graph could show. Several x(t)/y(t) pairs can be overlaid with independent t ranges for comparison. The most common surprise: the shape depends entirely on the chosen t interval, so a range that stops early truncates the curve before it closes, and one that runs too long retraces the same path on top of itself.

Worked example

A concrete input and expected output from the current implementation.

Input

x(t) = cos(t), y(t) = sin(2t), t from 0 to 2*pi

Expected output

A figure-eight lying along the x-axis, bounded within x in [-1,1] and y in [-1,1]. It starts and ends at (1,0), and crosses itself at the origin (0,0) at t = pi/2 and t = 3*pi/2.

x has period 2*pi while y = sin(2t) has period pi, so the point returns to y = 0 twice as often as x completes its cycle; at t = pi/2 and 3*pi/2, x = 0 and y = 0 coincide, producing the self-intersection at the origin that gives this Lissajous curve its figure-eight shape.

How the result is produced

1

Sampling, not solving

The plotter evaluates x(t) and y(t) at a series of t values spaced across the range you supply, then connects consecutive (x,y) points with line segments. It does not solve for an algebraic relation between x and y. Curves with sharp cusps, tight loops, or high-frequency oscillation (like Lissajous figures with large ratios) need a range with enough samples per cycle or the plotted path looks faceted instead of smooth.

2

Independent overlays and animated trace

Each curve you add carries its own x(t), y(t), and t range, so curves with different periods or domains can be compared on one canvas without forcing a shared scale. The animated trace replays the same sampled points in order as t increases, which is why reversing or narrowing the t range changes what the animation shows, not just the static plot.

Good uses

  • checking whether a hand-derived parametric form (e.g. converting a polar curve r(theta) into x = r cos(theta), y = r sin(theta)) actually produces the shape you expected before using it elsewhere
  • visualizing Lissajous-style figures to see how changing a frequency ratio or phase offset in x(t) versus y(t) reshapes the curve
  • overlaying a family of curves (e.g. an epicycloid at several radius ratios) to compare how one parameter changes the shape

Limits and checks

  • the tool draws sampled line segments, not an analytic curve, so cusps or tightly looping sections can look faceted or lose detail if the sample density is too low for that stretch of the range
  • it won't detect or flag self-intersections, discontinuities, or an incomplete loop for you; if the t range is too short the curve simply stops mid-shape with no warning that it never closed
  • expressions are typed in plain math notation (sin, cos, t, pi, etc.), not LaTeX, so pasting a LaTeX-formatted equation from a textbook or paper will not parse without rewriting it first

Common questions

Can I plot a polar curve like r = 1 + cos(theta) with this?

Yes, but you have to convert it yourself first: set x(t) = (1 + cos(t)) * cos(t) and y(t) = (1 + cos(t)) * sin(t), then plot t over the range that closes the curve (0 to 2*pi for this one). The tool doesn't accept r(theta) directly.

Does it report arc length, curvature, or the points where the curve crosses itself?

No. The description covers plotting, animated tracing, adjustable ranges, and overlay of multiple curves - it does not mention computing derived quantities like arc length, curvature, or self-intersection coordinates, so treat any of those as something you'd need to work out separately.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

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