Geometric Construction 8

Trochoid

The epitrochoid is the path of a point rigidly attached to a circle rolling externally upon a fixed fixed circle. The hypotrochoid is the path of a point rigidly attached to a circle rolling internally upon a fixed fixed circle. Construct the trochoids according to these definitions.

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Construct the tangent to each of the curves constructed above.

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Construct the double generation of each of the curves constructed above.

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Construct the trochoids and their tangents according to the principle of center of gravity.