Differentiability implies continuity This is easy to prove using the limit of the difference quotient
Weistrass function is continuous everywhere but not differentiable everywhere
No.
An intuitive answer (NOTE: this is far from precise!) A function is continuous if you can trace its graph without lifting your pencil from the page. If, additionally, it is smooth everywhere without any jagged edges or abrupt corners, then it is differentiable. It is not possible for a function to be differentiable but not continuous. On the other hand, plenty of functions are continuous without being differentiable.
All differentiable functions need be continuous at least.
Classical optimization methods are analytical and useful in finding the optimum solution of differentiable and continuous functions. They do have limited scope in practical applications.
Definition: A function f is differentiable at a if f'(a) exists. it is differentiable on an open interval (a, b) [or (a, ∞) or (-∞, a) or (-∞, ∞)]if it is differentiable at every number in the interval.Example: Where is the function f(x) = |x| differentiable?Answer:1. f is differentiable for any x > 0 and x < 0.2. f is not differentiable at x = 0.That's mean that the curve y = |x| has not a tangent at (0, 0).Thus, both continiuty and differentiability are desirable properties for a function to have. These properties are related.Theorem: If f is differentiable at a, then f is continuous at a.The converse theorem is false, that is, there are functions that are continuous but not differentiable. (As we saw at the example above. f(x) = |x| is contionuous at 0, but is not differentiable at 0).The three ways for f not to be differentiable at aare:a) if the graph of a function f has a "corner" or a "kink" in it,b) a discontinuity,c) a vertical tangent
There are infinitely many types of functions. For example: Discrete function, Continuous functions, Differentiable functions, Monotonic functions, Odd functions, Even functions, Invertible functions. Another way of classifying them gives: Logarithmic functions, Inverse functions, Algebraic functions, Trigonometric functions, Exponential functions, Hyperbolic functions.
Wherever a function is differentiable, it must also be continuous. The opposite is not true, however. For example, the absolute value function, f(x) =|x|, is not differentiable at x=0 even though it is continuous everywhere.
The existence of a derivative function at a given point depends on the behavior of the original function at that point. A derivative exists at a point if the function is continuous and has a defined slope (i.e., is differentiable) at that point. However, there are functions that are not differentiable at certain points—such as those with sharp corners, vertical tangents, or discontinuities—meaning the derivative does not exist for all values of ( x ). Thus, while many functions are differentiable everywhere, not all functions possess derivatives across their entire domain.
Both are polynomials. They are continuous and are differentiable.
If the graph of the function is a continuous line then the function is differentiable. Also if the graph suddenly make a deviation at any point then the function is not differentiable at that point . The slope of a tangent at any point of the graph gives the derivative of the function at that point.
Domain, codomain, range, surjective, bijective, invertible, monotonic, continuous, differentiable.