Aldis, W. Steadman (William Steadman), 1839-1928 · Cambridge [Eng.] Deighton, Bell, and co.; London, G. Bell and sons · leaf 23
nes of OP and OQrespectively, OQ cos e = OM. I + MN. m + NQ. n = OQ . r . I + OQ . m . m + OQ . n .n; .. cos 6 = ir + mm + nn. >^ 13. To find the distance of a j^oint from the origin luhenthe co-ordinates are oblique. The formulae of Arts. 4, 5, 6 and 8 were obtained on thesupposition of… … will be clearly the same whatever be the position of P, pro-vided it lie in the same straight line through 0. Theseratios are called the direction-ratios of the line OP, and areusually denoted by the letters I, in, n. We then get formulae-corresponding to those of Alt. (5), x = l.OP, y = m. OP, z =…
