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Specialist Mathematics Β· Unit 2 Β· Complex arithmetic and algebra Β· Complex arithmetic using polar form

Use the modulus |𝑧| of a complex number 𝑧 and the principal argument Arg(𝑧) of a non-zero complex number 𝑧. |𝑧| = βˆšπ‘Ž2 + 𝑏2 Arg(𝑧) = πœƒ, tan(πœƒ) = 𝑏 π‘Ž, βˆ’πœ‹ < πœƒ ≀ πœ‹, π‘Ž β‰  0

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Question 1

Three complex numbers are given in the table below. For each complex number, find the modulus and the principal argument, giving your argument in radians to 2 decimal places.

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Question 2

Let \(w = 3 - 4i\) and \(z = -2 + 5i\). (a) Determine \(|w|\). (1 mark) (b) Determine \(\text{Arg}(z)\), giving your answer in radians correct to two decimal places. (2 marks) (c) Determine \(\text{Arg}\left(\frac{w}{z}\right)\), giving your answer in radians correct to two decimal places. (1 mark)

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Question 3

What is the principal argument Arg(z) of the complex number z = -1 + √3i?

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Understand the difference between the argument, arg(𝑧), and the principal argument, Arg(𝑧) of a non-zero complex number 𝑧. arg(𝑧) = Arg(𝑧) + 2πœ‹π‘›, 𝑛 ∈ β„€
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