Year 12 Integration (Polynomials) Worksheet — Level 3 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 12 calculus worksheet.
Year 12 Integration (Polynomials) Worksheet — Level 3 — Practice Set 4 — Answers
Use the rule ∫ xⁿ dx = xⁿ⁺¹ / (n+1) + C.
1.Evaluate ∫ from 0 to 2 of (8x3 + 12x2 + 3) dx
Answer: 70
- ∫ 8x3 dx = 2x4
- ∫ 12x2 dx = 4x3
- ∫ 3 dx = 3x
- F(x) = 2x4 + 4x3 + 3x
- F(2) − F(0) = 70 − (0) = 70
2.Evaluate ∫ from 0 to 1 of (−3x2 − 6x + 3) dx
Answer: −1
- ∫ −3x2 dx = −x3
- ∫ −6x dx = −3x2
- ∫ 3 dx = 3x
- F(x) = −x3 − 3x2 + 3x
- F(1) − F(0) = −1 − (0) = −1
3.Evaluate ∫ from 2 to 4 of (−8x3 + 4x − 3) dx
Answer: −462
- ∫ −8x3 dx = −2x4
- ∫ 4x dx = 2x2
- ∫ −3 dx = −3x
- F(x) = −2x4 + 2x2 − 3x
- F(4) − F(2) = −492 − (−30) = −462
4.Evaluate ∫ from 0 to 3 of (−4x3 + 12x2 − 2) dx
Answer: 21
- ∫ −4x3 dx = −x4
- ∫ 12x2 dx = 4x3
- ∫ −2 dx = −2x
- F(x) = −x4 + 4x3 − 2x
- F(3) − F(0) = 21 − (0) = 21
5.Find ∫ (20x4 + 8x + 3) dx
Answer: 4x5 + 4x2 + 3x + C
- ∫ 20x4 dx = 4x5
- ∫ 8x dx = 4x2
- ∫ 3 dx = 3x
- Don't forget the constant of integration, C
6.Evaluate ∫ from 0 to 2 of (−15x4 − 3x2 + 1) dx
Answer: −102
- ∫ −15x4 dx = −3x5
- ∫ −3x2 dx = −x3
- ∫ 1 dx = x
- F(x) = −3x5 − x3 + x
- F(2) − F(0) = −102 − (0) = −102
7.Evaluate ∫ from 2 to 3 of (−10x4 − 4x3 + 3) dx
Answer: −484
- ∫ −10x4 dx = −2x5
- ∫ −4x3 dx = −x4
- ∫ 3 dx = 3x
- F(x) = −2x5 − x4 + 3x
- F(3) − F(2) = −558 − (−74) = −484
8.Evaluate ∫ from 2 to 3 of (10x4 + 4x3 − 3x2) dx
Answer: 468
- ∫ 10x4 dx = 2x5
- ∫ 4x3 dx = x4
- ∫ −3x2 dx = −x3
- F(x) = 2x5 + x4 − x3
- F(3) − F(2) = 540 − (72) = 468
9.Find ∫ (−10x4 − 8x3 − 4x) dx
Answer: −2x5 − 2x4 − 2x2 + C
- ∫ −10x4 dx = −2x5
- ∫ −8x3 dx = −2x4
- ∫ −4x dx = −2x2
- Don't forget the constant of integration, C
10.Find ∫ (8x3 − 6x2 + 8x) dx
Answer: 2x4 − 2x3 + 4x2 + C
- ∫ 8x3 dx = 2x4
- ∫ −6x2 dx = −2x3
- ∫ 8x dx = 4x2
- Don't forget the constant of integration, C
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.