Multivariable chain rule (video) | Khan Academy
www.khanacademy.org › v › multivariable-chain-ruleIf we take the ordinary derivative, with respect to t, of a composition of a multivariable function, in this case just two variables, x of t, y of t, where we're plugging in two intermediary functions, x of t, y of t, each of which just single variable, the result is that we take the partial derivative, with respect to x, and we multiply it by the derivative of x with respect to t, and then we add to that the partial derivative with respect to y, multiplied by the derivative of y with ...