| William Leybourn - Geometry - 1704 - 432 pages
...the Co-fine of half the Sum of the Sides, Is to the Co fine of half the Difference of the Sides 5 So **is the Co- tangent of half the Vertical Angle, To the Tangent of** half the Sum of the Angle. COROLLARIES. In any Spherical Triangle, t Tan. f Bafe : Tan. f Sum or the... | |
| Enoch Lewis - Conic sections - 1844 - 240 pages
...lined triangle, having two unequal sides ; as the less of those sides is to the greater, so is radius **to the tangent of an angle ; and as radius is to the** tangent of the excess of that angle above half a right angle, so is the tangent of half the sum of... | |
| Samuel Alsop - Surveying - 1865 - 440 pages
...48", side, 165.49. RULE 2. 14L .As the less of the two given sides is to the greater, so is radius **to the tangent of an angle; and as radius is to the** tangent of the excess of this angle above 45°, so is the tangent of the half sum of the opposite angles... | |
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