Aldis, W. Steadman (William Steadman), 1839-1928 · Cambridge [Eng.] Deighton, Bell, and co.; London, G. Bell and sons · leaf 26
s by a plane through R, M, N, is evidently one-sixthof the above expression. - 15. The position of a point in space is sometimes de-termined by means of polar co-ordinates. Thus if Ox, Oy,Oz be rectangular axes and P any point, the position of P isclearly determined if we know OP the distance of P… … plane of zx. These are called the polar co-ordinates of Pand are usually denoted by the letters r, 6, (p. They areconnected with the rectangular co-ordinates of P referred tothe axes Ox, Oy, Oz by very simple relations which canbe obtained thus. Draw FN parallel to Oz to meet thel)lane of xy in iV,…
