Elements of plane and spherical trigonometry (1833)
Young, J. R. (John Radford), 1799-1885 · Philadelphia, Carey, Lea & Blanchard · leaf 59
d. cos. opp.;and to retain this in the memory we have only to remember that thevowels in the contractions mid., adja., opp., are the same as those in thecontractions sin., tan., cos., to which they are joined. That these rules comprehend all the equations given above will beseen by taking a, b, c,… … As in the solution of right-angled triangles two parts are given tofind a third, vre mast ia the application of uNapiers rule choose for themiddle of these three parts that Tvhich causes the other two to becomeeither adjacent parts or opposite parts. EXAMPLES. (53.) 1. In the right-angled triangle…
