 | Euclid, John Playfair - Euclid's Elements - 1846 - 334 pages
...difference of the angles opposite to them : and also that the cosine of half the sum of these sides, is to the cosine of half their difference, as the cotangent of half the angle contained between them, to the tangent of half the sum of the angles opposite to them. COR. 2.... | |
 | Charles William Hackley - Trigonometry - 1851 - 536 pages
...: : tan 4 a : tan 4 (b — c) . . . That is, the cosine of half the sum of two sides of a spherical triangle is to the cosine of half their difference, as the cotangent of half the included angle is to the tangent of half ike sum of the other two angles. The second may be repeated in a similar... | |
 | Charles William Hackley - Trigonometry - 1851 - 524 pages
...: tan i (6 — c) . . . That is, the cosine of half the sum of two sides of a spherical triangle it to the cosine of half their difference, as the cotangent of half the included angle is to the tangent of half the sum of the other two angles. The second may be repeated in a similar... | |
 | Benjamin Peirce - Trigonometry - 1852 - 398 pages
...once obtained by applying § 79 to the polar triangle. 91. Theorem. The cosine of half the sum of tico sides of a triangle is to the cosine of half their...difference, as the cotangent of half the included, angle is to the tangent of half the sum of the other tico angles, or in (figs. 32 and 33), cos. J (a + c)... | |
 | Benjamin Peirce - Trigonometry - 1861 - 396 pages
...(369) Proof. This theorem is at once obtained by applying (350) to the polar triangle. »• jf 91. Theorem. The cosine of half the sum of two sides of...of half their difference as the cotangent of half tJie included angle is to the tangent of half the sum of the other two angles ; or, in ABO (fig. 32... | |
 | Benjamin Greenleaf - Geometry - 1861 - 638 pages
...cot £ C : tan £ (4 — B). (187) That is, The cosine of half the sum of two sides of a spherical triangle is to the cosine of half their difference as the cotangent of half the included angle is to the tangent of half the sum of the other two angles. The sine of half the sum of two sides of... | |
 | Benjamin Greenleaf - Geometry - 1862 - 518 pages
...: cot JC : tan £ (4 — #). (187) That is, y^e cosine of half the sum of two sides of a spherical triangle is to the cosine of half their difference as the cotangent of half the included angle is to the tangent of half the sum of the other two angles. The sine of half the sum of two sides of... | |
 | Benjamin Greenleaf - Geometry - 1862 - 532 pages
...the other two angles. The sine of half the sum of two sides of a spherical triangle is to the sine of half their difference as the cotangent of half the included angle is to the tangent of haJf the difference of the other two angles. By applying (186) and (187) to the... | |
 | Benjamin Greenleaf - Geometry - 1863 - 504 pages
...cot £ C : tan £ (4 — B). (187) That is, The cosine of half the sum of two sides of a spherical triangle is to the cosine of half their difference as the cotangent of half the included angle is to the tangent of half the sum of the other two angles. The sine of half the sum of two sides of... | |
 | Benjamin Greenleaf - 1869 - 516 pages
...: cot i C : tan £ (^ — 5). (187) That is, The cosine of half the sum of two sides of a spherical triangle is to the cosine of half their difference as the cotangent of half the included angle is to the tangent of half the sum of the other two angles. The sine of half the sum of two sides of... | |
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The cosine of half the sum of two sides of a spherical triangle is to the cosine of half their difference as the cotangent of half the included angle is to the tangent of half the sum of the other two angles. The sine of half the sum of two sides of a... 
