SPS SPS ASFM Statistics 2021 May — Question 1

Exam BoardSPS
ModuleSPS ASFM Statistics (SPS ASFM Statistics)
Year2021
SessionMay
TopicComplex Numbers Argand & Loci

  1. (a) The complex number \(3 + 2 \mathrm { i }\) is denoted by \(w\) and the complex conjugate of \(w\) is denoted by \(w ^ { * }\). Find
    1. the modulus of \(w\),
    2. the argument of \(w ^ { * }\), giving your answer in radians, correct to 2 decimal places.
      (b) Find the complex number \(u\) given that \(u + 2 u ^ { * } = 3 + 2 \mathrm { i }\).
      (c) Sketch, on an Argand diagram, the locus given by \(| z + 1 | = | z |\).
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  2. Find the value of \(k\) such that \(\left( \begin{array} { l } 1
    2
    1 \end{array} \right)\) and \(\left( \begin{array} { r } - 2
    3
    k \end{array} \right)\) are perpendicular. Two lines have equations \(l _ { 1 } : \mathbf { r } = \left( \begin{array} { l } 3
    2
    7 \end{array} \right) + \lambda \left( \begin{array} { r } 1
    - 1
    3 \end{array} \right)\) and \(l _ { 2 } : \mathbf { r } = \left( \begin{array} { l } 6
    5
    2 \end{array} \right) + \mu \left( \begin{array} { r } 2
    1
    - 1 \end{array} \right)\).
  3. Find the point of intersection of \(l _ { 1 }\) and \(l _ { 2 }\).
  4. The vector \(\left( \begin{array} { l } 1
    a
    b \end{array} \right)\) is perpendicular to the lines \(l _ { 1 }\) and \(l _ { 2 }\). Find the values of \(a\) and \(b\).
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