UMBC Dept of Math & Stat

MATH 423, Assignment of February 16, 2022

Due on Monday February 21

The involute of a parabola

The parabola $y = x^2$ may be expressed as the parametric curve $\boldsymbol{\alpha}(u) = \langle u, u^2 \rangle$. Find a parametric equation $\boldsymbol{\beta}(u)$ of the involute that starts at the parabola's vertex.

The static and animated diagrams below correspond to the parameter range $0 \le u \le 1$. See what you can do to produce similar diagrams. Yours need not be exactly like mine.

[involute-of-parabola.png] [involute-of-parabola.gif]

A parabola is one of the rare curves whose involutes may be expressed symbolically in terms of elementary functions. The circle and the cycloid are another two such curves.

Wrapping around a circle

The diagrams below show a line segment of length $2\pi$ unwrapping off of a unit circle. Can you produce those diagrams? Yours need not be exactly like mine.

[wrap-around-circle.png] [wrap-around-circle.gif]

This demo's wrapping operation is applied (twice) to produce the animated torus on the course's main web page.



Author: Rouben Rostamian