dly wrote: > It is just clearer when you know what arc tan is and then why it relates
> just briefly in between the J Donna: I thought this explanation was pretty clear: [snip] arctan=:_3&o. angle =:12&o. For real y, arctan y is the angle between _1r2p1 and 1r2p1 whose tangent is y. For real x and y, angle x+j.y is the angle from the x-axis to (x,y), between _1p1 and 1p1. If x>0, arctan y%x is the same as angle x+j.y, but not if x<:0. [/snip] There is some J in it, but then this is a J group. Someone who uses J's o. functions can be assumed to know something about complex numbers and their representation as the Argand diagram. I know what orthogonal vectors are: I just did not think it relevant to mention them, and I have to assume some context. Again, please feel free to write up something if you think this is unclear or presuming too much. Best wishes, John ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
