OCR FP1 2010 June — Question 10

Exam BoardOCR
ModuleFP1 (Further Pure Mathematics 1)
Year2010
SessionJune
TopicComplex Numbers Arithmetic
TypeSquare roots with follow-up application

10 The complex number \(z\), where \(0 < \arg z < \frac { 1 } { 2 } \pi\), is such that \(z ^ { 2 } = 3 + 4 \mathrm { i }\).
  1. Use an algebraic method to find \(z\).
  2. Show that \(z ^ { 3 } = 2 + 11 \mathrm { i }\). The complex number \(w\) is the root of the equation $$w ^ { 6 } - 4 w ^ { 3 } + 125 = 0$$ for which \(- \frac { 1 } { 2 } \pi < \arg w < 0\).
  3. Find \(w\).