CSEC MATHEMATICS · MODULE 3 · LESSON C5

Non-Linear Graphs, Distance–Time and Speed–Time Graphs

Graphs of y = a/x, y = a/x² and y = ax³, distance–time and speed–time graphs, and solving problems that combine linear and non-linear graphs.

Higher Concepts in Secondary Level MathematicsM3 2.4M3 2.5M3 2.6≈ 45 min🎮 3 games
Before you start

By the end of this lesson you can…

Step 1 · Watch

Explainer video

5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.

LESSON C5 · EXPLAINER

Non-Linear Graphs, Distance–Time and Speed–Time Graphs

A car speeds up, cruises, then brakes. A graph of its speed tells you the acceleration (the slope) and the distance travelled (the area).

Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.

Explore in 3D

Speed–time graphs

Change the journey and read acceleration and distance.

Step 2 · Read

Key notes

Copy these into your notebook in your own words — that is how they stick.

y = a/x

Hyperbola with two branches; asymptotes the axes; x ≠ 0.

y = a/x²

Both branches on the same side of the x-axis (sign of a); symmetric about the y-axis.

y = ax³

Smooth S-curve through the origin; rotational symmetry about the origin.

Distance–time

Gradient = speed; flat = stationary; negative gradient = returning.

Average speed

Total distance ÷ total time.

Speed–time

Gradient = acceleration; area = distance; flat = constant speed.

Area

Split into triangles, rectangles or trapeziums: trapezium ½(a + b)h.

Intersection

The x-values where two graphs meet solve the equation f(x) = g(x).

EXAM TIPS & COMMON MISTAKES

  • Draw both branches of a reciprocal graph — and never join them across the gap.
  • On speed–time graphs, area gives distance — include units: m, not m/s.
  • Read gradient as rise ÷ run using a large triangle on the straight part of the graph.
  • Give solutions from a graph to a sensible accuracy (1 decimal place) and say “from the graph”.
Play & practise

Games

3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Mathematics Arcade.

Step 3 · Practise

Paper 1 practice — multiple choice

8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.

CSEC Paper 01 style · SO 2.4

1. The graph of y = 8/x

Answer: A. It is a hyperbola in two branches that never meets the axes.
CSEC Paper 01 style · SO 2.4

2. When x = −2, the value of y = 8/x is

Answer: B. 8 ÷ (−2) = −4.
CSEC Paper 01 style · SO 2.4

3. The graph of y = x³ passes through

Answer: C. 0³ = 0; the other points do not satisfy y = x³.
CSEC Paper 01 style · SO 2.5

4. On a distance–time graph, a horizontal line represents an object that is

Answer: D. Distance is not changing as time passes.
CSEC Paper 01 style · SO 2.5

5. The gradient of a distance–time graph represents

Answer: A. Change in distance ÷ change in time = speed.
CSEC Paper 01 style · SO 2.5

6. A car’s speed increases from 0 to 20 m/s in 10 seconds. Its acceleration is

Answer: B. 20 ÷ 10 = 2.
CSEC Paper 01 style · SO 2.5

7. A car travels at 20 m/s for 30 seconds. The distance travelled is the area under the speed–time graph, which is

Answer: C. 20 × 30 = 600 m.
CSEC Paper 01 style · SO 2.6

8. The graphs of y = 8/x and y = x + 2 intersect where x equals

Answer: D. 8 = x² + 2x → (x + 4)(x − 2) = 0.
Step 4 · Apply

Paper 2 practice — structured questions

Write full answers, then reveal the mark scheme and tick the points you earned (19 marks in total). Show all your working — method marks count. Your answers are saved on this device.

CSEC Paper 02 style · Module 3 (Speed–time graph)

Question 1 [9 marks]

A car starts from rest and accelerates uniformly to 20 m/s in 10 seconds. It then travels at 20 m/s for 20 seconds and finally slows uniformly to rest in 10 seconds.

(a) Sketch the speed–time graph (axes labelled, points (0, 0), (10, 20), (30, 20), (40, 0)). [3]

MARK SCHEME — (a) (max 3)

(b) Calculate the acceleration during the first 10 seconds and the deceleration in the last 10 seconds. [3]

MARK SCHEME — (b) (max 3)

(c) Calculate the total distance travelled. [3]

MARK SCHEME — (c) (max 3)

CSEC Paper 02 style · Module 3 (Combining graphs)

Question 2 [10 marks]

A table of values is needed for y = 8/x for x = ±1, ±2, ±4, ±8.

(a) Complete the table for y = 8/x. [2]

MARK SCHEME — (a) (max 2)

(b) On the same axes, draw the graphs of y = 8/x and y = x + 2. (Check: two smooth branches; line through (0, 2) and (−2, 0).) [4]

MARK SCHEME — (b) (max 4)

(c) Use the graph to solve 8/x = x + 2 and show algebraically that your answers are correct. [4]

MARK SCHEME — (c) (max 4)

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Sources

Where this topic appears in CSEC papers

Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.