This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ... =CA. Move the trammel about in any way always keeping M and N upon the minor and major axis, then P traces out the ellipse. From this construction another is evident. Make circles centre C, and distances respectively CA and CB. Draw any radius CRQ; from R draw a parallel to CA, and from Q a parallel to CB meeting it ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ... =CA. Move the trammel about in any way always keeping M and N upon the minor and major axis, then P traces out the ellipse. From this construction another is evident. Make circles centre C, and distances respectively CA and CB. Draw any radius CRQ; from R draw a parallel to CA, and from Q a parallel to CB meeting it at P. The point P is on the curve. By taking different positions of the radius CRQ we can find any number of points on the curve. (129) To describe an ellipse within a given parallelogram to touch the sides at their middle points. Let PQSR be the parallelogram D, G, E, F the middle points of the sides. DE and GF are diameters of the ellipse, and are called conjugates, because each diameter is parallel to the tangents at the extremities of the other. Divide one of the semi-diameters into any number of equal parts and number the divisions as shewn in the figure. Divide half of one of the sides of the parallelogram adjacent into the same number of equal parts, numbering the divisions in the order given. Join corresponding points to extremities of the other diameter. The intersections give points on the curve. If the parallelogram were a square we should obtain a circle, and in this case the proof of the construction is deduced from the fact that the lines intersect at right angles and their intersections lie on a circle. If this figure (of the square and circle) were drawn on the glass of a window in dark lines, the shadow of the figure on any white plane surface within the room would be figure 129. (130) An ellipse being given to find its centre, axes, and the tangent and normal at any point. Draw any two parallel chords in the ellipse. Find their middle points, join them, this line produced both ways is a diameter which bisected gives the centre, .
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Add this copy of Geometrical Drawing. With Notes and Examples...: Plane to cart. $58.41, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2019 by Wentworth Press.
