OCR MEI C1 — Question 6 4 marks

Exam BoardOCR MEI
ModuleC1 (Core Mathematics 1)
Marks4
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicCircles
TypeFind centre and radius from equation
DifficultyEasy -1.2 This is a straightforward application of completing the square to convert a circle equation to standard form. It requires only one technique (completing the square in x, noting y is already complete) and is a standard textbook exercise with no problem-solving element. Easier than average for A-level.
Spec1.03d Circles: equation (x-a)^2+(y-b)^2=r^21.03e Complete the square: find centre and radius of circle
6 The equation of a circle is \(x ^ { 2 } + y ^ { 2 } - 2 x - 8 = 0\).
Find the centre and radius of the circle.
Question 6:
AnswerMarks
\(x^2+y^2-2x-8=0\)M1
\(\Rightarrow (x-1)^2+y^2=8+1=9\)A1
Centre is \((1,0)\)B1
Radius \(= 3\)B1
Total: 4
## Question 6:
$x^2+y^2-2x-8=0$ | M1 |
$\Rightarrow (x-1)^2+y^2=8+1=9$ | A1 |
Centre is $(1,0)$ | B1 |
Radius $= 3$ | B1 |
**Total: 4**

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6 The equation of a circle is $x ^ { 2 } + y ^ { 2 } - 2 x - 8 = 0$.\\
Find the centre and radius of the circle.

\hfill \mbox{\textit{OCR MEI C1  Q6 [4]}}
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