Britannica 11th · 11th edition

Trisectrix

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OCR text aligned to scanned pagesVol. 27, pp. 292-2921910–1911

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This entry is linked to Encyclopaedia Britannica, 11th edition. The cited range is Vol. 27, pp. 292-292.

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TRISECTRIX, a curve which is a variety of the limacon (q.v.) of Pascal, and named from its property of trisecting an angle. The polar equation is r=i + 2 cos 6 and the form of the curve is shown in the figure. To trisect an angle by means of this curve, ov describe a circle with centre O and radius OE, and let the given angle which is to be trisected be laid off from OE and cut the circle at S; let the chord ES cut the trisectrix in J. Then OJ trisects the given angle.