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A function is differentiable at an interior point a of its domain if and only if it is semi-differentiable at a and the left derivative is equal to the right derivative. An example of a semi-differentiable function, which is not differentiable, is the absolute value function () = | |, at a = 0. We find easily () =, + = If a function is semi ...
Semiderivative or Semi-derivative may refer to: One-sided derivative of semi-differentiable functions Half-derivative , an operator H {\displaystyle H} that when acting twice on a function f {\displaystyle f} gives the derivative of f {\displaystyle f} .
As shown below, the second-derivative test is mathematically identical to the special case of n = 1 in the higher-order derivative test. Let f be a real-valued, sufficiently differentiable function on an interval I ⊂ R {\displaystyle I\subset \mathbb {R} } , let c ∈ I {\displaystyle c\in I} , and let n ≥ 1 {\displaystyle n\geq 1} be a ...
Thus, the second partial derivative test indicates that f(x, y) has saddle points at (0, −1) and (1, −1) and has a local maximum at (,) since = <. At the remaining critical point (0, 0) the second derivative test is insufficient, and one must use higher order tests or other tools to determine the behavior of the function at this point.
Combining derivatives of different variables results in a notion of a partial differential operator. The linear operator which assigns to each function its derivative is an example of a differential operator on a function space. By means of the Fourier transform, pseudo-differential operators can be defined which allow for fractional calculus.
A differentiable function. In mathematics, a differentiable function of one real variable is a function whose derivative exists at each point in its domain.In other words, the graph of a differentiable function has a non-vertical tangent line at each interior point in its domain.
The second-derivative test for functions of one and two variables is simpler than the general case. In one variable, the Hessian contains exactly one second derivative; if it is positive, then x {\displaystyle x} is a local minimum, and if it is negative, then x {\displaystyle x} is a local maximum; if it is zero, then the test is inconclusive.
The 1971 Ph.D. Thesis by Dimitri P. Bertsekas (Proposition A.22) [3] proves a more general result, which does not require that (,) is differentiable. Instead it assumes that (,) is an extended real-valued closed proper convex function for each in the compact set , that ( ()), the interior of the effective domain of , is nonempty, and that is continuous on the set ( ()).