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Intervals Where Function Is Continuous Calculator

Reviewed by Calculator Editorial Team

Determining where a function is continuous is a fundamental concept in calculus. This calculator helps you find the intervals where a function is continuous by analyzing its definition and potential points of discontinuity.

What Is Continuity in Functions?

A function is continuous at a point if there are no jumps, breaks, or holes at that point. More formally, a function f(x) is continuous at a point c if three conditions are met:

  1. The function is defined at c (f(c) exists)
  2. The limit of f(x) as x approaches c exists
  3. The limit equals the function value (lim x→c f(x) = f(c))

If a function is continuous at every point in an interval, it is continuous on that interval. Points where the function is not continuous are called points of discontinuity.

Note: A function can be continuous everywhere except at specific points, or it can be discontinuous everywhere.

How to Find Continuity Intervals

To find where a function is continuous, follow these steps:

  1. Identify the domain of the function (all x-values where the function is defined)
  2. Look for points where the function might be discontinuous:
    • Points where the denominator is zero (for rational functions)
    • Points where the function is not defined (like square roots of negative numbers)
    • Points where the function has a jump discontinuity
  3. Check the limit of the function as x approaches each potential point of discontinuity
  4. Determine if the limit equals the function value at that point
  5. Combine the intervals where the function is continuous

The continuity intervals are the intervals where the function meets all three continuity conditions.

Using the Calculator

Our calculator helps you determine the continuity intervals for a given function. Simply enter the function in the provided field, and the calculator will analyze it to find where the function is continuous.

The calculator uses the following approach:

  1. Parses the function to identify potential points of discontinuity
  2. Checks the limit at each potential point
  3. Determines if the function is continuous at each point
  4. Combines the intervals where the function is continuous

Formula used: The calculator analyzes the function f(x) and checks for continuity at all points in its domain, excluding points where the function is not defined or has a discontinuity.

Examples of Continuity Intervals

Let's look at a few examples to understand how continuity intervals work.

Example 1: Polynomial Function

Consider the function f(x) = x² + 3x + 2.

This is a polynomial function, and polynomials are continuous everywhere. Therefore, the function is continuous on the interval (-∞, ∞).

Example 2: Rational Function

Consider the function f(x) = (x² - 4)/(x - 2).

This function has a point of discontinuity at x = 2 because the denominator becomes zero. The function is continuous everywhere else, so the continuity intervals are (-∞, 2) and (2, ∞).

Example 3: Piecewise Function

Consider the piecewise function:

f(x) = {
    x + 1, if x < 0
    x², if x ≥ 0
}

This function has a point of discontinuity at x = 0 because the left-hand limit (1) does not equal the right-hand limit (0). The function is continuous on (-∞, 0) and [0, ∞).

FAQ

What is the difference between continuity and differentiability?

A function can be continuous at a point but not differentiable there. For example, the absolute value function f(x) = |x| is continuous everywhere but differentiable everywhere except at x = 0.

How do I know if a function is continuous at a point?

To check if a function is continuous at a point c, verify that the function is defined at c, the limit as x approaches c exists, and the limit equals the function value at c.

Can a function be continuous on an open interval but not on a closed interval?

Yes, a function can be continuous on an open interval (a, b) but not on the closed interval [a, b] if the function is not continuous at the endpoints a or b.

What are the common types of discontinuities?

The common types of discontinuities are removable discontinuities (where the limit exists but doesn't equal the function value), jump discontinuities (where the left and right limits exist but are not equal), and infinite discontinuities (where the limit is infinite).