public function getSlope($dp = 0)
    {
        if ($dp != 0) {
            return round(exp($this->slope), $dp);
        }

        return exp($this->slope);
    }
public function getSlope($dp = 0)
    {
        if ($dp != 0) {
            return round(exp($this->slope), $dp);
        }

        return exp($this->slope);
    }
Return the Slope of the line.

@param int $dp Number of places of decimal precision to display

@return float