(idea) by xdc Sat Nov 13 1999 at 14:28:15
The inverse function to the cosine.

If y is the cosine of theta, then theta is the arccosine of y.

del.icio.us Facebook Digg StumbleUpon Reddit   (I like it!)
(idea) by nobody really Wed Nov 05 2003 at 0:05:59
arccos(z) is equal to − i × ln(z + √(z² − 1)) since cos(φ) = cosh(i × φ).

The arccosine is real for -1 ≤ x ≤ 1 only. Values are then between 0 and π. (I had originally written defined instead of real, thanks to IWhoSawTheFace for pointing out this ridiculous error to me)
del.icio.us Facebook Digg StumbleUpon Reddit   (I like it!)
Y'know, if you log in, you can write something here, or contact authors directly on the site. Create a New User if you don't already have an account.