calculation of angles gatfix at hotmail.com Fri Dec 17 06:41:39
EST 1999 I see that in many modelling programs where an angle
theta is to be calculated, it is very often calculated as
atan2(sin(theta),cos(theta)), where atan2, according to the
manual, is a FORTRAN function approximately equal to I don't
understand: (a) why atan2(y,x) is preferred to atan(y/x); (b)
why one couldn't directly take acos(cos(theta)) or
asin(sin(theta)), instead of having to obtain both sine and
cosine. (the cosine of angle is easy to obtain, but sine is
not). Any help appreciated. Mark Sent via Deja.com
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