OCR C1 — Question 9 10 marks

Exam BoardOCR
ModuleC1 (Core Mathematics 1)
Marks10
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicTangents, normals and gradients
TypeFind tangent at given point (polynomial/algebraic)
DifficultyStandard +0.3 This is a multi-part C1 question requiring standard differentiation to find a tangent, completing the square, and describing transformations. Part (iv) adds mild problem-solving by connecting previous parts, but all techniques are routine and well-practiced at this level. Slightly above average due to the synthesis required in part (iv).
Spec1.02e Complete the square: quadratic polynomials and turning points1.02w Graph transformations: simple transformations of f(x)1.07m Tangents and normals: gradient and equations

9. (i) Find an equation for the tangent to the curve \(y = x ^ { 2 } + 2\) at the point \(( 1,3 )\) in the form \(y = m x + c\).
(ii) Express \(x ^ { 2 } - 6 x + 11\) in the form \(( x + a ) ^ { 2 } + b\) where \(a\) and \(b\) are integers.
(iii) Describe fully the transformation that maps the graph of \(y = x ^ { 2 } + 2\) onto the graph of \(y = x ^ { 2 } - 6 x + 11\).
(iv) Use your answers to parts (i) and (iii) to deduce an equation for the tangent to the curve \(y = x ^ { 2 } - 6 x + 11\) at the point with \(x\)-coordinate 4.

Question 9:
Part (i):
AnswerMarks Guidance
AnswerMark Notes
\(\frac{dy}{dx} = 2x\)M1
\(\text{grad} = 2\)A1
\(\therefore y-3 = 2(x-1)\)M1
\(y = 2x+1\)A1
Part (ii):
AnswerMarks Guidance
AnswerMark Notes
\(= (x-3)^2 - 9 + 11 = (x-3)^2 + 2\)M1 A1
Part (iii):
AnswerMarks Guidance
AnswerMark Notes
Translation by 3 units in the positive \(x\)-directionB2
Part (iv):
AnswerMarks Guidance
AnswerMark Notes
\(y = 2(x-3)+1 \quad [y = 2x-5]\)M1 A1 (10)
# Question 9:

## Part (i):
| Answer | Mark | Notes |
|--------|------|-------|
| $\frac{dy}{dx} = 2x$ | M1 | |
| $\text{grad} = 2$ | A1 | |
| $\therefore y-3 = 2(x-1)$ | M1 | |
| $y = 2x+1$ | A1 | |

## Part (ii):
| Answer | Mark | Notes |
|--------|------|-------|
| $= (x-3)^2 - 9 + 11 = (x-3)^2 + 2$ | M1 A1 | |

## Part (iii):
| Answer | Mark | Notes |
|--------|------|-------|
| Translation by 3 units in the positive $x$-direction | B2 | |

## Part (iv):
| Answer | Mark | Notes |
|--------|------|-------|
| $y = 2(x-3)+1 \quad [y = 2x-5]$ | M1 A1 | **(10)** |

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9. (i) Find an equation for the tangent to the curve $y = x ^ { 2 } + 2$ at the point $( 1,3 )$ in the form $y = m x + c$.\\
(ii) Express $x ^ { 2 } - 6 x + 11$ in the form $( x + a ) ^ { 2 } + b$ where $a$ and $b$ are integers.\\
(iii) Describe fully the transformation that maps the graph of $y = x ^ { 2 } + 2$ onto the graph of $y = x ^ { 2 } - 6 x + 11$.\\
(iv) Use your answers to parts (i) and (iii) to deduce an equation for the tangent to the curve $y = x ^ { 2 } - 6 x + 11$ at the point with $x$-coordinate 4.\\

\hfill \mbox{\textit{OCR C1  Q9 [10]}}