Definition:Epicycloid/Generator/Epicycle
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Definition
Let an epicycloid be generated by rolling a circle $C_1$ around the outside of another circle $C_2$.
The circle $C_1$ can be referred to as the epicycle of the epicycloid.
Also known as
An epicycle of an epicycloid is also known as a rotor.
The term has been taken by $\mathsf{Pr} \infty \mathsf{fWiki}$ from the children's toy Spirograph, which itself was taken from the term rotor as applied to the moving (rotating) part of a rotary machine.
Also see
- Results about epicycloids can be found here.
Linguistic Note
The term epicycle in this context was used by Apollonius of Perga in his exposition on epicycloids.
Sources
- 1989: Ephraim J. Borowski and Jonathan M. Borwein: Dictionary of Mathematics ... (previous) ... (next): epicycloid
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): epicycle
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): epicycloid
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): epicycle
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): epicycloid