Paper 1: Pure Mathematics 1 October 2021, Question 7 9 marks
The circle C has equation
Find
the coordinates of the centre of C,
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the exact radius of C, giving your answer as a simplified surd.
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The line l has equation y = 3x + k where k is a constant.
Given that l is a tangent to C,
find the possible values of k, giving your answers as simplified surds.
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