Books Books
... projection is that of a meridian, or one parallel thereto, and the point of sight is assumed at an infinite distance on a line normal to the plane of projection and passing through the center of the sphere. A circle which is parallel to the plane...
Trigonometry, Plane and Spherical: With the Construction and Application of ... - Page 79
by Thomas Simpson - 1810 - 125 pages

Cyclomathesis: Or, An Easy Introduction to the Several Branches of ..., Volume 7

William Emerson - Mathematics - 1769 - 370 pages
...flevation ,er inclination. PROP. II. A circle perpendicular to the plane of proje8io», is £rojected into a right line equal to its diameter. For projecting lines drawn through all the points jjf the circle fall in the common feclion of the planes A 4 of Fig. of the circle and of projection,...

The projection of the sphere, orthographic, stererographic, and gnomonical ...

William Emerson - 1769 - 86 pages
...tangent, of CD,, or co- tangent, of CdA... 9.ED • •'•'.•*. • ••• Cor. i. A great circk perpendicular to the plane of projection is projected into a right, line pajjing thro' the cente' of projection ; and.an% arch is projefted into its correspondent tangent....

Tracts: Containing: I. Mechanics, Or the Doctrine of Motion: II.

William Emerson - Centrifugal force - 1793 - 386 pages
...of the circle ; becaufe the planes interfect in that diameter. ^ E- DCor. Hence any plane figure , perpendicular to the plane of projection is projected into a right line. For the perpendiculars from every point, will all fall in the common interfettion of the figure with...

A Philosophical and Mathematical Dictionary: Containing an ..., Volume 2

Charles Hutton - Astronomy - 1815 - 686 pages
...when л в is parallel to the plane of the projection. 5. Hence it is evident, that a line parallel to the plane of projection, is projected into a right line equal to itself; but a line that is oblique to the plane of projection, is projected into one that is less than...

Elements of Plane and Spherical Trigonometry: With Their Applications to ...

Olinthus Gregory - Plane trigonometry - 1816 - 276 pages
...Therefore st = tan PD = ft. . . , Consequently, the tangent Pt of an arc of a great circle terminated at the plane of projection, is projected into a right line equal to it. Let pt, and rt', two such tangents, be connected by the right line tt' which will _ be in the plane...

A Popular Course of Pure and Mixed Mathematics ...: With Tables of ...

Peter Nicholson - Mathematics - 1825 - 372 pages
...d, and perpendicular to Cd ; and Cd is the tangent of CD, or co-tangent of Cd\. QED Car. I. A great circle, perpendicular to the plane of projection, is projected into a right line pasting through the centre of projection ; ami any arc is projected into its corresponding tangent....

A Treatise on Plane and Spherical Trigonometry: Including the Construction ...

Enoch Lewis - Conic sections - 1844 - 228 pages
...projected into a figure similar and equal to itself. ART. 138. A circle whose plane is at right angles to the plane of projection, is projected into a right line equal to its diameter. Let EF be the plane of projection, seen edgewise ; ABDC, the circle; GH, IK, right lines perpendicular...

Library of Universal Knowledge, Volume 1

Encyclopedias - 1880 - 890 pages
...the sphere. A circle wliirh is parallel to the plane of projection is projected into an equal circle; a circle perpendicular to the plane of projection is projected into a right line equal in length to the diameter of the projected circle; a circle in any other position is projected into...