Complex Numbers & Argand Diagrams (Edexcel A Level Further Maths: Core Pure): Exam Questions

Exam code: 9FM0

19 mins3 questions
1a4 marks

space straight f left parenthesis z right parenthesis equals z to the power of 4 plus a z cubed plus b z squared plus c z plus d

where a comma space b comma space c and d are real constants.

Given that negative 1 plus 2 straight i and 3 minus straight i are two roots of the equation straight f left parenthesis z right parenthesis equals 0

Show all the roots of space straight f left parenthesis z right parenthesis equals 0 on a single Argand diagram.

1b5 marks

Find the values of a comma space b comma space c and d.

2a3 marks

In an Argand diagram, the points A and B are represented by the complex numbers negative 3 plus 2 straight i and 5 minus 4 straight i respectively. The points A and B are the end points of a diameter of a circle C.

Find the equation of C comma giving your answer in the form 

vertical line z minus a vertical line equals b      a element of straight complex numbersb element of straight real numbers

2b
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6 marks

The circle D, with equation vertical line z minus 2 minus 3 straight i vertical line equals 2, intersects C at the points representing the complex numbers z subscript 1 and z subscript 2

Find the complex numbers z subscript 1 and z subscript 2

31 mark

straight f left parenthesis z right parenthesis equals z to the power of 4 plus a z cubed plus 6 z squared plus b z plus 65

where a and b are real constants.

Given that z equals 3 plus 2 straight i is a root of the equation straight f left parenthesis z right parenthesis equals 0, show the roots of straight f left parenthesis z right parenthesis equals 0  on a single Argand diagram.