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A cos 6 = cos a cos c + sin a sin c cos B cos c = cos a cos 6 + sin a sin 6 cos C Law of Cosines for Angles cos A = — cos B...
An Elementary Treatise on Plane & Spherical Trigonometry: With Their ... - Page 172
by Benjamin Peirce - 1845 - 449 pages

## Mémoires couronnés et autres mémoires publiés par l'Académie ..., Volume 15

...on représente par A, B, C les angles et par «, 6, B c les côtés opposés, la formule générale cos A = — cos B cos C + sin B . sin C . cos a , où l'on doit poser C = 90°, donne cos A = sin B . cos «. On a, d'ailleurs, r cos a — — > sin...

## Spherical Trigonometry: For the Use of Colleges and Schools

Isaac Todhunter - Spherical trigonometry - 1863 - 182 pages
...base and A the opposite angle of one triangle, arid a and A' similar quantities for the other. Then cos a = cos b cos c + sin b sin c cos A, cos a' = cos b cos c + sin b sin c cos A'; therefore cos a - cos a' = sin b sin c (cos A — cos A')...

## Elements of Geometry: With Practical Applications to Mensuration

Benjamin Greenleaf - Geometry - 1863 - 504 pages
...cos a = -^OC* + ~W "* A' ' Substituting the functions derived from the triangles 0 A' O A' O, we have cos a = cos b cos c -)- sin b sin c cos A. In like manner may be deduced cos b = cos c cos a -)- sin c sin a cos B, cos c = cos a cos b -)- sin...

## Traité de cinématique

J.-B. Belanger - Kinematics - 1864 - 348 pages
...trois angles plans a, b, e d'un angle dièdre et de l'angle dièdre A opposé à la face a, . savoir : cos a = cos b cos c + sin b sin c cos A en faisant « = T, 6 = « et c = j3+-, ce qui donne 0 = —cos y. sin j3 -f- sin a. cos j3 cos A, d'où...

## Spherical Astronomy

Franz Brünnow - 1865 - 584 pages
...we have found in No. 2, we get the following formulae, which are true for every spherical triangle : cos a = cos b cos c -+- sin b sin c cos A sin a sin 5 = sin b sin, A sin a cos B = cos b sin c — sin b cos c cos A. These are the three principal...

## Spherical Astronomy ...

Franz Brünnow - 1865 - 592 pages
...we have found in No. 2, we get the following formulae, which are true for every spherical triangle : cos a = cos b cos c + sin b sin c cos A gin a sin B = sin .•'• sin I sin o cos-B= cosi sin r. — sin i cos c cos A. These are the three...

## Tratado elemental de trigonometria: escrito de Real Orden para uso de los ...

Saturnino Montojo - 1865 - 302 pages
...Q,6a= 90°. De esta fórmula («) podremos ya deducir por la permutacion indicada (39) las siguientes cos a = cos b cos c + sin b sin c cos A \ cos b = cos c cos a + sin c sin a cos B > («, „) cos c = cos a cos b + sin a sin b cos C ,•...

## A collection of elementary test questions in pure and mixed mathematics ...

James Robert Christie - Mathematics - 1866 - 426 pages
...adjacent parts. (2) Sine of middle part = product of cosines of opposite parts. In any spherical triangle, cos a= cos b, cos c — sin. b, sin c. cos A ; . . sin(*-6)sin(se) , sins, sin (*-a) Sin * A = - -. - ; - : - I COS * A = - T - . — : - : am b...

## Mathematical Exercises ...

Samuel H. Winter - 1867 - 472 pages
...c cos A. Sin A : sin B : sin C : : sin a : sin b : sin c. Cot a sin b = cot A sin C + cos b cos C ; cos A = — cos B cos C + sin B sin C cos a. Sin i A = A / J»in(,-*)sin(,-C)) CQS ^ A = \/ \ sm b sin c } I /sin s sin (sa) \ ;tanJLA_ / ism (sb)am...

## A Book of Mathematical Problems on Subjects Included in the Cambridge Course

Joseph Wolstenholme - Mathematics - 1867 - 370 pages
...y" + a9 - 2ya cOS <f> i , 0+^ + ,/r=o prove that y3y sin 0 + ya sin <^> + a/3 sin if/ = 0. 297. If cos A + cos B cos C + sin B sin C cos A = 0, then will tan ^45° ± ^\ tan ^45" - |) tan ^45° - £) = - 1 ; and if cos A = cos B cos C ±...