public static function arctan($z) {
        if (!($z instanceof Complex)) $z = static::parse($z);

        $I = new Complex(0,1);
        $iz = static::mul($z, $I);
        $w = static::div( static::add(1, $iz), static::sub(1, $iz) );
        $logw = static::log($w);
        return static::div($logw, new Complex(0,2));
    }
public static function arctan($z) {
        if (!($z instanceof Complex)) $z = static::parse($z);

        $I = new Complex(0,1);
        $iz = static::mul($z, $I);
        $w = static::div( static::add(1, $iz), static::sub(1, $iz) );
        $logw = static::log($w);
        return static::div($logw, new Complex(0,2));
    }
public static function arctan ( $ z ) { if ( ! ( $ z instanceof Complex ) ) $ z = static :: parse ( $ z ) ; $ I = new Complex ( 0 , 1 ) ; $ iz = static :: mul ( $ z , $ I ) ; $ w = static :: div ( static :: add ( 1 , $ iz ) , static :: sub ( 1 , $ iz ) ) ; $ logw = static :: log ( $ w ) ; return static :: div ( $ logw , new Complex ( 0 , 2 ) ) ; }
complex inverse tangent function

Complex::arctan($z) computes and returns the principal branch of arctan($z)


@param mixed $z (Complex, or parsable to Complex)
@retval Complex
complex inverse tangent function