A function f(x) is continuous at x=c if: 1) f(c) is defined, 2) $\lim_{x \to c} f(x)$ exists, and 3) $\lim_{x \to c} f(x) = f(c)$.

A function is discontinuous at x=c if at least one of the three conditions for continuity is not met: f(c) is undefined, $\lim_{x \to c} f(x)$ does not exist, or $\lim_{x \to c} f(x) \neq f(c)$.

The left-hand limit is the value that f(x) approaches as x approaches c from values less than c, denoted as $\lim_{x \to c^-} f(x)$.

The right-hand limit is the value that f(x) approaches as x approaches c from values greater than c, denoted as $\lim_{x \to c^+} f(x)$.

A removable discontinuity occurs when $\lim_{x \to c} f(x)$ exists, but either f(c) is undefined or $\lim_{x \to c} f(x) \neq f(c)$. It can be 'removed' by redefining f(c).

A jump discontinuity occurs when the left-hand limit and the right-hand limit both exist but are not equal: $\lim_{x \to c^-} f(x) \neq \lim_{x \to c^+} f(x)$.

An infinite discontinuity occurs when the function approaches infinity (or negative infinity) as x approaches c from either the left or right, often associated with vertical asymptotes.

An oscillating discontinuity occurs when the function oscillates infinitely many times near a point, preventing the limit from existing.

The domain of a function is the set of all possible input values (x-values) for which the function is defined.

The range of a function is the set of all possible output values (y-values) that the function can produce.

Look for jumps, holes (open circles), or vertical asymptotes. These indicate points where the function is not continuous.

A smooth, unbroken curve indicates that the function is continuous over that interval. There are no sudden jumps or breaks.

A vertical asymptote indicates an infinite discontinuity. The function is not continuous at the x-value where the asymptote occurs.

An open circle indicates a removable discontinuity (a hole). The function is not defined at that specific x-value, or the limit does not equal the function value.

A jump in the graph indicates a jump discontinuity. The left-hand limit and the right-hand limit exist but are not equal.

Check if the pieces of the graph connect smoothly at the points where the function definition changes. There should be no gaps or jumps.

If a function is differentiable, its graph is smooth and continuous. There are no sharp corners, cusps, or discontinuities.

The graph of $f(x) = \frac{1}{x}$ has a vertical asymptote at x = 0, indicating a discontinuity at that point. The function is continuous everywhere else.

The graph of $f(x) = |x|$ is continuous everywhere. Although it has a sharp corner at x = 0, it is still continuous at that point.

Trace the graph from both the left and right sides towards the x-value of interest. If the y-values approach the same number, that number is the limit.

Continuity is crucial because it allows us to apply many theorems and techniques, such as the Intermediate Value Theorem and the Mean Value Theorem. It ensures predictable behavior of functions.

Each condition plays a specific role. f(c) being defined ensures there's a value at the point. The limit existing ensures the function approaches a single value. The limit equaling f(c) ensures there's no jump or hole.

For a function to be continuous at a point, the limit at that point must exist. This means the left-hand limit and the right-hand limit must be equal.

Visually, a function is continuous if its graph can be drawn without lifting your pen. There should be no jumps, breaks, or holes in the graph at the point in question.

If a function is differentiable at a point, it must also be continuous at that point. However, the converse is not always true; a function can be continuous but not differentiable (e.g., at a sharp corner).

Rational functions are discontinuous where the denominator is equal to zero, because division by zero is undefined. This creates a vertical asymptote or a hole in the graph.

The Intermediate Value Theorem states that if a function is continuous on a closed interval [a, b], then for any value k between f(a) and f(b), there exists a c in [a, b] such that f(c) = k. Continuity is a requirement for this theorem.

One-sided limits (left-hand and right-hand limits) are crucial for determining continuity at endpoints of intervals or at points where the function's definition changes. For continuity, both one-sided limits must exist and be equal to the function's value at that point.

Continuity is used in physics to model motion, in engineering to design structures, and in economics to analyze market trends. It ensures that models behave predictably and realistically.

Piecewise functions are defined by different expressions on different intervals. Continuity must be checked at the points where the function definition changes to ensure the pieces connect smoothly.