Wikipedia:Reference desk/Archives/Mathematics/2015 October 21

= October 21 =

Angles to all three axes, symmetrical equation?
Let p be a point in the first octant. Let a be the angle between OP and the X axis, b be the angle between OP and the Y axis and c be the angle between OP and the Z axis. Is there a symmetrical equation that allows any one of the three to be calculated from the other two? My guess is that it is Cos^2(a)+Cos^2(b)+Cos^2(c)=1, but I'm not sure of any examples that would show that other than those on the XY, YZ or XZ planes.Naraht (talk) 17:59, 21 October 2015 (UTC)
 * See Direction cosine. --RDBury (talk) 18:10, 21 October 2015 (UTC)
 * Thanx, perfect.Naraht (talk) 19:32, 21 October 2015 (UTC)