This is documentation for Mathematica 6, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)


gives the cosine of z.
  • Mathematical function, suitable for both symbolic and numerical manipulation.
  • The argument of Cos is assumed to be in radians. (Multiply by Degree to convert from degrees.)  »
  • Cos is automatically evaluated when its argument is a simple rational multiple of ; for more complicated rational multiples, FunctionExpand can sometimes be used.  »
  • For certain special arguments, Cos automatically evaluates to exact values.
  • Cos can be evaluated to arbitrary numerical precision.
  • Cos automatically threads over lists.
New in 1