∑ DANEMATHICS
FREE CAPS MATHS RESOURCES
Grade 12 · Calculus
Differentiation: The Rules and How Exams Use Them
MEMORANDUM
Name:
Class:
Date:
Mark
/ 20
Answer all questions. Show all your working — marks are awarded for method as well as the final answer. Teacher copy: accept any correct equivalent method.
- 1Differentiate y = x4. (power rule)(2)4x3✓✓ (2)
- 2Differentiate y = 5x3 − 2x2 + 7. (polynomial)(2)15x2 − 4x✓✓ (2)
- 3Differentiate y = 2x2 − 3x + 9. (polynomial)(2)4x − 3✓✓ (2)
- 4Differentiate y = 3⁄x (write as 3x−1). (rewrite)(2)−3x−2 = −3⁄x2✓✓ (2)
- 5Differentiate y = x (write as x^12). (rewrite)(2)12x^(−12) = 1⁄(2x)✓✓ (2)
- 6From first principles, differentiate f(x) = 3x. (first principles)(2)[3(x+h)−3x]/h = 3h/h = 3✓✓ (2)
- 7Gradient of y = x2 + 2x at x = 1. (gradient)(2)2x+2 at x=1 = 4✓✓ (2)
- 8Gradient of y = x3 at x = 2. (gradient)(2)3x2 at x=2 = 12✓✓ (2)
- 9Find x where y = x2 − 6x has a turning point. (turning point)(2)2x−6 = 0 → x = 3✓✓ (2)
- 10Find the turning points of y = x3 − 12x. (turning point)(2)3x2−12=0 → x = ±2 → (2,−16) and (−2,16)✓✓ (2)
TOTAL: 20 marks