An elementary treatise on coordinate geometry of three dimensions (1912)
Bell, Robert J. T. (Robert John Tainsh), 1877-1963 · London : Macmillan and co., limited · leaf 42
circle. The minor axis Lacos#. AA; therefore if AA = 2a and co80=&/a, the minor axis La 2b.By § 19, the area of the ellipse = cos 6. ird2 = Tr/>. Ex. 2. Find the area of the section of the cylinder 10./- + 9y2 = 144by a plane whose normal makes an angle of 60° with OZ. Ans. lM-… … Fig. IS. Fig. 19. 21. Direction-cosines referred to rectangular axes.Let AOA be the line through O which lias direction-cosines cos a, cos/3, cosy. Let P, (x, y, z) be any point on AOA, 20 COORDINATE GEOMETRY [ch. ii. and OP have measure r. In fig. 18, r is positive; in fig. 19, r is negative. Draw…
Geometry, Analytic
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