Analyze behavior separately from the left and right of the target input. If each side approaches a finite level, compare those two results rather than averaging them or relying on the plotted point. Unequal one-sided limits identify the abrupt separation, while equal values would remove the specific jump-based obstruction to a single limit.
The function's value at the target input does not control the comparison of neighboring outputs. Changing that isolated value can leave both one-sided limits unchanged, so it cannot eliminate their disagreement. This distinction lets analysis separate the behavior of the branches near the point from the separately assigned point value.
Classification depends on limiting behavior, not merely on whether a graph looks broken. A jump has two finite one-sided limits that disagree; a removable discontinuity is associated with a common limiting value that may not match the defined point, whereas an infinite discontinuity involves unbounded behavior. These categories distinguish different causes of failure.
For a piecewise function, first locate the input where the formula or branch changes. Then evaluate the approach from inputs smaller than that point and from inputs larger than it. Record the two one-sided results and compare them. This workflow identifies whether the transition creates a jump, instead of depending only on the function's displayed value.
On a graph, inspect the branch approached from each side of the target input. Separate endpoint heights indicate the two limiting levels, even if a filled or open point appears at the location itself. Reading the branches this way connects visual vertical separation with the algebraic one-sided-limit test.
In models with sudden transitions, the one-sided limits describe the output level expected immediately before and immediately after the threshold. A disagreement signals that the model changes between distinct nearby levels rather than varying through one common limiting value. This perspective makes jump discontinuities useful for interpreting piecewise equations, graphs, and abrupt modeled changes.