2016 ACJC P1 Q8

2016 ACJC P1 Q8

6 marks
Prelims

The complex number \(z\) is given by \(z=k+\mathbf{i}\) where \(k\) is a non-zero real number.

  1. Find the possible values of \(k\) if \(z=k+\mathbf{i}\) satisfies the equation \({{z}^{3}}-\mathbf{i}{{z}^{2}}-2z-4\mathbf{i}=0\).[3]
  2. For the complex number \(z\) found in part (i) for which \(k>0\), find the smallest integer value of \(n\) such that \(\left| {{z}^{n}} \right|>100\) and \({{z}^{n}}\) is real.[3]

Video Solution:

Video Solution

Video solution locked

A free account saves your progress; this video needs a course plan.

Solution:

Solution locked

680+ questions here come with free worked solutions. A free account saves your questions and progress; this one needs a course plan.

Answer:(i) k = ±√3; (ii) n = 12

Need help? Join our JC Math tuition classes.

Learn more