For a continuously differentiable function of several real variables, a point (that is, a set of values for the input variables, which is viewed as a point in ) is critical if all of the partial derivatives of the function are zero at , or, equivalently, if its gradient is zero. The critical values are the values of the function at the critical points.
For a continuously differentiable function of several real variables, a point (that is, a set of values for the input variables, which is viewed as a point in ) is critical if all of the partial derivatives of the function are zero at , or, equivalently if its gradient is zero. The critical values are the values of the function at the critical points.