Calculus 2 Lecture Notes, Section 9.7

The rectangular coordinate equation for this orientation is , where , which implies that , and that the directrix is at Theorem 7.2: Polar equations for conic sections with different directrixes. The conic section with eccentricity e > 0, focus (0, 0) and the indicated directrix has the polar equation:, if the directrix is the line x = d > 0. ................
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