Maths Tool

4 Piecewise Function Calculator

Solve values across four rules with visual feedback. Track boundaries, inclusions, and interval behavior effortlessly. Build confidence through examples, exports, formulas, graphs, and FAQs.

Current Result

Results appear here after each submission.

Input x
2
Matched piece
Piece 3
Active interval
(1, 4)
Expression used
abs(x) + 2
f(x)
4

Calculator Inputs

Enter four rules, define intervals, choose inclusions, and test one x-value.

Piece 1
Piece 2
Piece 3
Piece 4
Evaluation Settings

Supported functions: abs, sqrt, sin, cos, tan, asin, acos, atan, log, exp, floor, ceil, round.

Plotly Graph

The graph shows the complete four-piece function over the selected domain.

Example Data Table

These sampled points help verify interval switching and function output.

Sample x Matched Piece Interval f(x)
-10 None Outside all defined intervals Undefined
-8.32636 1 (-10, -2) 70.328268
-6.65272 1 (-10, -2) 45.258679
-4.979079 1 (-10, -2) 25.791233
-3.305439 1 (-10, -2) 11.925929
-1.631799 2 (-2, 1) -0.263598
0.041841 2 (-2, 1) 3.083682
1.715481 3 (1, 4) 3.715481
3.389121 3 (1, 4) 5.389121
5.062762 4 (4, 10) 59.820461
6.736402 4 (4, 10) 146.109546
8.410042 4 (4, 10) 289.006058

Formula Used

A four-piece function selects one rule from four possible rules.

It depends on which interval contains the input value.

f(x) = { f₁(x), x in I₁;  f₂(x), x in I₂;  f₃(x), x in I₃;  f₄(x), x in I₄ }

Each interval can be open, closed, or mixed.

The calculator checks bounds and inclusion settings first.

Then it evaluates only the matching expression for x.

If x fits no interval, the result is undefined.

How to Use This Calculator

  1. Enter one expression for each of the four pieces.
  2. Set lower and upper bounds for every interval.
  3. Choose which interval endpoints are included.
  4. Enter the x-value you want to evaluate.
  5. Set graph minimum, maximum, and sample count.
  6. Click the calculate button to view the result.
  7. Review the graph and example table for verification.
  8. Use CSV or PDF export for records or classwork.

Frequently Asked Questions

1. What is a four-piece function?

It is a function defined by four different expressions. Each expression applies only on its assigned interval. The active formula changes when x crosses a breakpoint.

2. Why do interval inclusions matter?

Inclusions decide whether a boundary value belongs to a piece. A closed endpoint includes the boundary. An open endpoint excludes it. This prevents overlap or ambiguity.

3. What happens when x matches no interval?

The calculator returns an undefined result. This means the function has no assigned rule at that x-value. The graph also leaves that point empty.

4. Can pieces overlap?

You can enter overlapping intervals, but only the first matching piece is used. For accurate math work, define non-overlapping intervals whenever possible.

5. Which expressions can I enter?

You can use x, numbers, parentheses, powers, and common functions like abs, sqrt, sin, cos, tan, log, and exp. Keep expressions algebraic and simple.

6. Why does the graph show breaks?

Breaks appear where the function is undefined or where no interval covers a plotted x-value. They also help reveal jumps and domain gaps clearly.

7. What does the example table show?

The table lists sampled x-values across your graph range. It shows the matched piece, active interval, and output. This helps you validate transitions and rule selection.

8. When should I export CSV or PDF?

Use CSV for spreadsheets, assignment data, and records. Use PDF for sharing a printable summary, graph, and result details with teachers or teammates.

Notes

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.