June 2016 Paper 1 Q1
1 \(y = x^2(x - 10)\)
Work out \(\quad \dfrac{\mathrm{d}y}{\mathrm{d}x}\) [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| (\(y\) =) \(x^3 - 10x^2\) | B1 | |
| \(3x^2 - 20x\) | B2 ft | B1ft for each term ft their \(x^3 - 10x^2\) |
Additional guidance
The given product must be expanded correctly to score the first B1, the product may be implied.
Ignore correct simplification from incorrect differentiation, eg \(\ 3x - 20x = -17x\)
Differentiating a second time to get \(6x - 20\) scores B1 B1
Correct answer seen in working then \(30x^2 - 20x\) on the answer line scores full marks ... ignore their transcription error.
\(y = x^2 - 10x^2\) B0, \(\mathrm{d}y/\mathrm{d}x = 2x - 20x\) scores B1
\(y = x^3 - 10\) B0, \(\mathrm{d}y/\mathrm{d}x = 3x^2\) scores B2