Sample Mean and Covariance Calculator https://www.hscripts.com/scripts/JavaScript/covariance-calculator.php Online calculator which allows to find the sample mean, covariance between the two random variables. Copy and paste the code into your HTML page to use this sample mean and covariance calculator.

Difference Quotient Calculator https://www.easycalculation.com/differentiation/quotient-rule-derivative.php Calculate derivative of a function using quotient rule of derivatives method.