Year 12 Integration (Polynomials) Worksheet — Level 3 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 12 calculus worksheet.
Year 12 Integration (Polynomials) Worksheet — Level 3 — Practice Set 3 — Answers
Use the rule ∫ xⁿ dx = xⁿ⁺¹ / (n+1) + C.
1.Find ∫ (−15x4 + 4x + 1) dx
Answer: −3x5 + 2x2 + x + C
- ∫ −15x4 dx = −3x5
- ∫ 4x dx = 2x2
- ∫ 1 dx = x
- Don't forget the constant of integration, C
2.Find ∫ (−10x4 − 3x2 + 4x) dx
Answer: −2x5 − x3 + 2x2 + C
- ∫ −10x4 dx = −2x5
- ∫ −3x2 dx = −x3
- ∫ 4x dx = 2x2
- Don't forget the constant of integration, C
3.Evaluate ∫ from 1 to 3 of (20x4 − 4x3 + 3x2) dx
Answer: 914
- ∫ 20x4 dx = 4x5
- ∫ −4x3 dx = −x4
- ∫ 3x2 dx = x3
- F(x) = 4x5 − x4 + x3
- F(3) − F(1) = 918 − (4) = 914
4.Evaluate ∫ from 1 to 3 of (4x3 + 12x2 − 2x) dx
Answer: 176
- ∫ 4x3 dx = x4
- ∫ 12x2 dx = 4x3
- ∫ −2x dx = −x2
- F(x) = x4 + 4x3 − x2
- F(3) − F(1) = 180 − (4) = 176
5.Find ∫ (−8x3 − 6x2 − 3) dx
Answer: −2x4 − 2x3 − 3x + C
- ∫ −8x3 dx = −2x4
- ∫ −6x2 dx = −2x3
- ∫ −3 dx = −3x
- Don't forget the constant of integration, C
6.Find ∫ (−10x4 + 2x + 3) dx
Answer: −2x5 + x2 + 3x + C
- ∫ −10x4 dx = −2x5
- ∫ 2x dx = x2
- ∫ 3 dx = 3x
- Don't forget the constant of integration, C
7.Find ∫ (−5x4 + 2x + 3) dx
Answer: −x5 + x2 + 3x + C
- ∫ −5x4 dx = −x5
- ∫ 2x dx = x2
- ∫ 3 dx = 3x
- Don't forget the constant of integration, C
8.Find ∫ (5x4 − 8x3 − 3x2) dx
Answer: x5 − 2x4 − x3 + C
- ∫ 5x4 dx = x5
- ∫ −8x3 dx = −2x4
- ∫ −3x2 dx = −x3
- Don't forget the constant of integration, C
9.Evaluate ∫ from 0 to 3 of (5x4 − 2x − 2) dx
Answer: 228
- ∫ 5x4 dx = x5
- ∫ −2x dx = −x2
- ∫ −2 dx = −2x
- F(x) = x5 − x2 − 2x
- F(3) − F(0) = 228 − (0) = 228
10.Evaluate ∫ from 2 to 5 of (−4x3 + 2x + 4) dx
Answer: −576
- ∫ −4x3 dx = −x4
- ∫ 2x dx = x2
- ∫ 4 dx = 4x
- F(x) = −x4 + x2 + 4x
- F(5) − F(2) = −580 − (−4) = −576
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.
Great work. Here's what to try next: