ReferenceExpressionsTrigonometryCosineReturn the cosine of a.cos( a )# Return the cosine of a. Description# cos( a ) Return the cosine of a, where a is the angle in radians. Parameters# a Angle in radians Return value# cosine of a Example usage# cos( PI/2 ) Returns 0. Last updated Sep 2, 2019PreviousArc TangentNextSine