Search results
Results from the WOW.Com Content Network
If all the partial derivatives of a function exist in a neighborhood of a point x 0 and are continuous at the point x 0, then the function is differentiable at that point x 0. However, the existence of the partial derivatives (or even of all the directional derivatives ) does not guarantee that a function is differentiable at a point.
The pointwise limit function need not be continuous, even if all functions are continuous, as the animation at the right shows. However, f is continuous if all functions f n {\displaystyle f_{n}} are continuous and the sequence converges uniformly , by the uniform convergence theorem .
In mathematics, the Weierstrass function, named after its discoverer, Karl Weierstrass, is an example of a real-valued function that is continuous everywhere but differentiable nowhere. It is also an example of a fractal curve .
A function of class is a function of smoothness at least k; that is, a function of class is a function that has a k th derivative that is continuous in its domain. A function of class or -function (pronounced C-infinity function) is an infinitely differentiable function, that is, a function that has derivatives of all orders (this implies that ...
A Lipschitz function g : R → R is absolutely continuous and therefore is differentiable almost everywhere, that is, differentiable at every point outside a set of Lebesgue measure zero. Its derivative is essentially bounded in magnitude by the Lipschitz constant, and for a < b , the difference g ( b ) − g ( a ) is equal to the integral of ...
If an absolutely continuous function is defined on a bounded closed interval and is nowhere zero then its reciprocal is absolutely continuous. [5] Every absolutely continuous function (over a compact interval) is uniformly continuous and, therefore, continuous. Every (globally) Lipschitz-continuous function is absolutely continuous. [6] If f ...
This is because that function, although continuous, is not differentiable at x = 0. The derivative of f changes its sign at x = 0, but without attaining the value 0. The theorem cannot be applied to this function because it does not satisfy the condition that the function must be differentiable for every x in the open interval.
The class consists of all differentiable functions whose derivative is continuous; such functions are called continuously differentiable. Thus, a C 1 {\displaystyle C^{1}} function is exactly a function whose derivative exists and is of class C 0 {\displaystyle C^{0}} .