Perl 5 version 18.3 documentation

cos

  • cos EXPR

  • cos

    Returns the cosine of EXPR (expressed in radians). If EXPR is omitted, takes the cosine of $_ .

    For the inverse cosine operation, you may use the Math::Trig::acos() function, or use this relation:

    1. sub acos { atan2( sqrt(1 - $_[0] * $_[0]), $_[0] ) }