Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2015/paper-1/3/solution

Use completing the square to obtain
The locus is therefore a circle with centre and radius . It meets the horizontal axis at and and the vertical axis at ; its highest and lowest points are .
Figure 1.
The circle locus, its centre, and its coordinate-axis intersections
. Details.

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