## A treatise of trigonometry, plane and spherical, theoretical and practical ...: As likewise a treatise of stereographick and orthographick projection of the sphere ... Illustrated in the stereographick projection of the several cases in right and oblique angled, spherical triangles: so that the requisites may be found without calculation, by scale and compass |

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A Treatise of Trigonometry, Plane and Spherical, Theoretical and Practical ... Samuel Heynes No preview available - 2015 |

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Page 22 - In any triangle, the sides are proportional to the sines of the opposite angles, ie. t abc sin A sin B sin C...

Page 17 - Solution of Right-angled Triangles, obferve, that as different Sides are made Radius, fo the other Sides acquire different Names, which Names are either Sines, Tangents, or Secants, and are to be taken out of your Table, To find a Side, any Side may be made Radius : Then fay, as the Name of the Side given is to the Name of the Side required ; fo is the Side given to the Side required.

Page 87 - CO in p, and p lhall be the Point P projected. To the point P draw the Tangent APG and on any point thereof, as A, ereft a perpendicular AD, at right angles to the plane EBPL, and draw the lines PD, AC, DC: and the Angle^PZ) fhall be equal to the Spherical Angle contained between the plains AP C, DPC.

Page 25 - ... so is the square of the radius to the square of the sine of half their contained angle, as shown in Leslie's Geometry.

Page 53 - BC is to the radius (or the fine of the right angle at A) as the fine of the fide AC to the fine of the angle B. And, in like manner, the fine of BC is to...

Page 74 - The first shows that, the sum of the sines of two arcs is to the difference of those sines, as the tangent of half the sum of the arcs is to the tangent of half their difference.