Math lesson plan · 12th grade (Year 13 in England) · 60 minutes
Find a curve from its gradient and a point
Calculus
CCSS HSF.BF.B.4England: A-level Pure Mathematics
Objective and success criteria
Students will: Find a curve from its gradient and a point.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Integrate powers of x (indefinite integrals)
Leads to: the next skill in this area.
Materials: Graphing tool or graph paper, Scientific calculators, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 6 min
- Quick retrieval from earlier learning (Integrate powers of x (indefinite integrals)). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Find ∫ −6x² dx. Leave out the + C. → -2*x^3Prompt: Add 1 to the power, then divide by the new power.
- Find ∫ (−6x² − 2x + 4) dx. Leave out the + C. → -2x^3-x^2+4xPrompt: Integrate each term separately.
- Ravi needs ∫ 1/x² dx. Which answer is correct? (−2/x³ + C / 1/x + C / 1·ln x + C / −1/x + C) → −1/x + CPrompt: Rewrite as 1x^(−2).
Hook · 6 min
- Show a distance-time graph of a journey and ask how fast it was going at one exact moment.
- Share the objective: Find a curve from its gradient and a point. Read the success criteria together.
I do: model it · 12 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: dy/dx = −4x − 5 and the curve passes through (3, 4). Find y in terms of x.
- Step 1: y = −2x² − 5x + C
- Step 2: 4 = −33 + C → C = 37
- Step 3: y = −2x² − 5x + 37
- Answer: -2x^2-5x+37
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- dy/dx = −6x − 5 and the curve passes through (−3, 9). Find y in terms of x. → -3x^2-5x+21Prompt: Integrate to get y, including + C.
- A cyclist's velocity is v = 3 + 8t m/s. Starting from s = 0, how far has she travelled after 6 seconds? → 162Prompt: Displacement is the integral of velocity.
You do: independent practice · 17 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- A cyclist's velocity is v = 4 + 6t m/s. Starting from s = 0, how far has she travelled after 3 seconds? → 39Prompt: Displacement is the integral of velocity.
- dy/dx = −8x and the curve passes through (2, −1). Find y in terms of x. → -4x^2+15Prompt: Integrate to get y, including + C.
Watch out for
- Forgetting the constant of integration.
- Differentiating a product by multiplying the derivatives.
Support and stretch
Support
- Review first: Integrate powers of x (indefinite integrals).
- Use concrete materials: graphing tool or graph paper.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-12.
Free lesson plan from eurekami.com/lesson-plan-builder