ReferenceExcel FormulasSupported FormulasTANOn this pageTAN The TAN function returns the tangent of an angle specified in radians. Syntax =TAN(number) Parameters number: The angle in radians for which you want the tangent Examples =TAN(0) // Returns 0=TAN(PI()/4) // Returns 1 (approximately)=TAN(PI()) // Returns 0 (approximately)