Tcl Library Source Code

Ticket Change Details
Bounty program for improvements to Tcl and certain Tcl packages.
Tcl 2018 Conference, Houston/TX, US, Oct 15-19
Send your abstracts to
or submit via the online form by Aug 20.

Artifact ID: 810cde4f6d8f1e2a45e326d05cbc02a73bd3ae0d21a783fffecd96138b8e56d1
Ticket: 21fef042b91ca252fc2a20ead5cd05c2b51b1776
add sind ,cosd, etc to geometry functions
User & Date: arjenmarkus 2018-07-23 06:55:10

  1. Change icomment to:

    What I forgot to mention is that the implementation of the degrees version of sin, cos, etc. is such that multiples of 90 degrees will result in exact values, that is: sind(180) = 0, cosd(90) = 0, sind(90) = 1.

    This is achieved by reducing the angle to an interval -45 to 45 degrees first and keeping track of the quadrant (rotated over 45 degrees) in which the original angle lies. Then converting to radians and applying basic trigonometric formulae.

    No such claim of exactness is made for other angles for which one or more of the sine/cosine/... functions yield a rational value.

  2. Change login to "arjenmarkus"
  3. Change mimetype to "text/plain"