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.Find ∫ (−10x4 + 6x2 + 4) dx
Answer: −2x5 + 2x3 + 4x + C
- ∫ −10x4 dx = −2x5
- ∫ 6x2 dx = 2x3
- ∫ 4 dx = 4x
- Don't forget the constant of integration, C
2.Find ∫ (15x4 + 4x3 + 3x2) dx
Answer: 3x5 + x4 + x3 + C
- ∫ 15x4 dx = 3x5
- ∫ 4x3 dx = x4
- ∫ 3x2 dx = x3
- Don't forget the constant of integration, C
3.Evaluate ∫ from 0 to 2 of (−8x3 + 9x2 + 8x) dx
Answer: 8
- ∫ −8x3 dx = −2x4
- ∫ 9x2 dx = 3x3
- ∫ 8x dx = 4x2
- F(x) = −2x4 + 3x3 + 4x2
- F(2) − F(0) = 8 − (0) = 8
4.Evaluate ∫ from 0 to 3 of (10x4 − 3x2 − 1) dx
Answer: 456
- ∫ 10x4 dx = 2x5
- ∫ −3x2 dx = −x3
- ∫ −1 dx = −x
- F(x) = 2x5 − x3 − x
- F(3) − F(0) = 456 − (0) = 456
5.Evaluate ∫ from 0 to 2 of (20x4 + 8x3 − 6x) dx
Answer: 148
- ∫ 20x4 dx = 4x5
- ∫ 8x3 dx = 2x4
- ∫ −6x dx = −3x2
- F(x) = 4x5 + 2x4 − 3x2
- F(2) − F(0) = 148 − (0) = 148
6.Evaluate ∫ from 2 to 5 of (20x4 − 2x + 3) dx
Answer: 12360
- ∫ 20x4 dx = 4x5
- ∫ −2x dx = −x2
- ∫ 3 dx = 3x
- F(x) = 4x5 − x2 + 3x
- F(5) − F(2) = 12490 − (130) = 12360
7.Find ∫ (10x4 − 3x2 − 2) dx
Answer: 2x5 − x3 − 2x + C
- ∫ 10x4 dx = 2x5
- ∫ −3x2 dx = −x3
- ∫ −2 dx = −2x
- Don't forget the constant of integration, C
8.Evaluate ∫ from 2 to 4 of (−3x2 + 8x + 4) dx
Answer: 0
- ∫ −3x2 dx = −x3
- ∫ 8x dx = 4x2
- ∫ 4 dx = 4x
- F(x) = −x3 + 4x2 + 4x
- F(4) − F(2) = 16 − (16) = 0
9.Find ∫ (20x4 − 3x2 + 2x) dx
Answer: 4x5 − x3 + x2 + C
- ∫ 20x4 dx = 4x5
- ∫ −3x2 dx = −x3
- ∫ 2x dx = x2
- Don't forget the constant of integration, C
10.Find ∫ (−12x3 + 6x2 + 2x) dx
Answer: −3x4 + 2x3 + x2 + C
- ∫ −12x3 dx = −3x4
- ∫ 6x2 dx = 2x3
- ∫ 2x dx = x2
- 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.
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