Plane trigonometry, and its application to mensuration and land surveying. Accompanied with all the necessary logarithmic and trigonometric tables (1852)
Perkins, George R. (George Roberts), 1812-1876 · New York, D. Appleton · leaf 156
° =-i, as follows: A cos. APB - cos. 120° = - \ = ^-t^-—, . . . (1.) cos. BPC=cos. 120°=-i = ^ , . . (2.) 2 2yz v . cos. CPA = cos. 120° = - \ = £_2^L_£1 . . (3.) £i ZX By clearing of fractions and transposing, these equations read-ily become x2 + xy + y*=a?J . . . . (4.)tf + yz + J=W, .... (5.)z*… … 146 x = y = z = SURVEYING. k + cP-V + c2m [chap. XI. where £ = ±\Zf (a2 &2 + JV + ^a*)-* (a4 + &4 + c% m = ± V2 (a2 + &2 + c2) + 6 A. PROBLEM X. From three points in the same horizontal plane, whose dis-tances from each other are known, the angles of elevation of thesummit of a hill or…
Plane trigonometry · Surveying
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from Divina proportione : opera a tutti glingegni perspicaci e curiosi necessaria oue ciascun studioso di philosophia: prospettiua pictura sculptura: architectura: musica: e altre mathematice: suavissima: sotile: e admirabile doctrina consequira: e delecterassi: co[n] varie questione de secretissima scientia (1509)](https://img.insideoutlibrary.com/img/200/ia-divinaproportion00paci-88-142.webp)
