Elements of plane and spherical trigonometry (1833)
Young, J. R. (John Radford), 1799-1885 · Philadelphia, Carey, Lea & Blanchard · leaf 136
f another associated system, then eachof the triangles of one system is polar to one triangle of the other asso-ciated system. * In the Edinburgh Transactions the author of this supplement has investigatedLexells theorem by a novel analysis,—fAe geometry of spherical coordinates, whichdetermines in… … triangle of an asso- i^ SPHERICAL GEOMETRY. This is not the only cnrious property of the figure before us: and weshall put down a small selection from those we are in possession of,not doubting that on many accounts they will be interesting to thosegeometers who indulge in trigonometrical…
