This same point may also be described by giving the pair of real numbers (r,phi), where r is the distance to the origin O, and phi the angle between the X-axis and the line Oz.
この同じ点は、実数の組(r,phi) で表すこともできる。 r は原点 0 からの距離であり、phi はX軸と 0 と z を結ぶ線分がなす角である。 - JM
Copyright (c) 2001 Robert Kiesling. Copyright (c) 2002, 2003 David Merrill. The contents of this document are licensed under the GNU Free Documentation License. Copyright (C) 1999 JM Project All rights reserved.