# How do you find the interval where a function is differentiable?

## How do you find the interval where a function is differentiable?

The definition of differentiability is expressed as follows:

1. f is differentiable on an open interval (a,b) if lim h → 0 f ( c + h ) − f ( c ) h exists for every c in (a,b).
2. f is differentiable, meaning exists, then f is continuous at c.

## How do you find if something is differentiable at a point?

A function is said to be differentiable if the derivative of the function exists at all points in its domain. Particularly, if a function f(x) is differentiable at x = a, then f′(a) exists in the domain.

What does differentiable at a point mean?

A function is differentiable at a point when there’s a defined derivative at that point. This means that the slope of the tangent line of the points from the left is approaching the same value as the slope of the tangent of the points from the right.

### What does differentiable on an open interval mean?

A function f is differentiable at a point c if. exists. Similarly, f is differentiable on an open interval (a, b) if. exists for every c in (a, b). Basically, f is differentiable at c if f'(c) is defined, by the above definition.

### Why differentiability is defined on open interval?

Originally Answered: Why differentiation is defined on open interval and contiunity is on closed interval? Differentiation is defined on open sets because every point of an open set is member of a neighbourhoud.

What is the condition for differentiability?

A function f is differentiable at x=a whenever f′(a) exists, which means that f has a tangent line at (a,f(a)) and thus f is locally linear at the value x=a. Informally, this means that the function looks like a line when viewed up close at (a,f(a)) and that there is not a corner point or cusp at (a,f(a)).

#### How do you show differentiability?

To show that f is differentiable at all x∈R, we must show that f′(x) exists at all x∈R. Recall that f is differentiable at x if limh→0f(x+h)−f(x)h exists. And so we see that f is differentiable at all x∈R with derivative f′(x)=−5.

#### What are the conditions for differentiability?

Does differentiable mean continuous?

If a function is differentiable then it’s also continuous. This property is very useful when working with functions, because if we know that a function is differentiable, we immediately know that it’s also continuous.

## Where is a function not differentiable?

A function is not differentiable at a if its graph has a vertical tangent line at a. The tangent line to the curve becomes steeper as x approaches a until it becomes a vertical line. Since the slope of a vertical line is undefined, the function is not differentiable in this case.

## Is differentiability closed interval?

(ii) The function y = f (x) is said to be differentiable in the closed interval [a, b] if R f ′ (a) and L f ′ (b) exist and f ′ (x) exists for every point of (a, b).