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Theorem:
On the complex plane, OABC
is a parallelogram and
AB=AD,
CB=CE,
△ABD~△CEB,
∠BCE＝θ＝∠DAB.
Let D=(x', y') and E=(x, y), then
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Use for linkage: If we fixed the point O to the plane and the point D moves through the curve f(x, y), then the point E will describe a congruent curve F(x, y) and F(x, y) is rotated from f(x, y) about the point O at the angle θ.
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Reference: Robert C. Yates Geometrical Tools 1949 |
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