Area calculations in complex plane

A question is this type if and only if it requires calculating the exact area of a region defined by complex loci or inequalities on an Argand diagram.

11 questions · Standard +0.9

4.02k Argand diagrams: geometric interpretation4.02o Loci in Argand diagram: circles, half-lines
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Edexcel CP AS 2021 June Q5
10 marks Standard +0.8
5. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{8d7dcb9f-510c-42c7-bcac-6d6ab3ed6468-12_584_830_246_639} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} Figure 1 shows an Argand diagram.
The set \(P\), of points that lie within the shaded region including its boundaries, is defined by $$P = \{ z \in \mathbb { C } : a \leqslant | z + b + c \mathrm { i } | \leqslant d \}$$ where \(a\), \(b\), \(c\) and \(d\) are integers.
  1. Write down the values of \(a , b , c\) and \(d\). The set \(Q\) is defined by $$Q = \{ z \in \mathbb { C } : a \leqslant | z + b + c \mathrm { i } | \leqslant d \} \cap \{ z \in \mathbb { C } : | z - \mathrm { i } | \leqslant | z - 3 \mathrm { i } | \}$$
  2. Determine the exact area of the region defined by \(Q\), giving your answer in simplest form.
Edexcel CP AS 2024 June Q5
10 marks Standard +0.8
  1. Given that on an Argand diagram the locus of points defined by \(| z + 5 - 12 i | = 10\) is a circle,
    1. write down,
      1. the coordinates of the centre of this circle,
      2. the radius of this circle.
    2. Show, by shading on an Argand diagram, the set of points defined by
    $$| z + 5 - 12 i | \leqslant 10$$
  2. For the set of points defined in part (b), determine the maximum value of \(| z |\) The set of points \(A\) is defined by $$A = \{ z : 0 \leqslant \arg ( z + 5 - 20 i ) \leqslant \pi \} \cap \{ z : | z + 5 - 12 i | \leqslant 10 \}$$
  3. Determine the area of the region defined by \(A\), giving your answer to 3 significant figures.
Edexcel CP2 2024 June Q5
9 marks Standard +0.8
  1. The locus \(C\) is given by
$$| z - 4 | = 4$$ The locus \(D\) is given by $$\arg z = \frac { \pi } { 3 }$$
  1. Sketch, on the same Argand diagram, the locus \(C\) and the locus \(D\) The set of points \(A\) is defined by $$A = \{ z \in \mathbb { C } : | z - 4 | \leqslant 4 \} \cap \left\{ z \in \mathbb { C } : 0 \leqslant \arg z \leqslant \frac { \pi } { 3 } \right\}$$
  2. Show, by shading on your Argand diagram, the set of points \(A\)
  3. Find the area of the region defined by \(A\), giving your answer in the form \(p \pi + q \sqrt { 3 }\) where \(p\) and \(q\) are constants to be determined.
Edexcel CP2 Specimen Q6
13 marks Challenging +1.8
  1. (a) (i) Show on an Argand diagram the locus of points given by the values of \(z\) satisfying
$$| z - 4 - 3 \mathbf { i } | = 5$$ Taking the initial line as the positive real axis with the pole at the origin and given that \(\theta \in [ \alpha , \alpha + \pi ]\), where \(\alpha = - \arctan \left( \frac { 4 } { 3 } \right)\),
(ii) show that this locus of points can be represented by the polar curve with equation $$r = 8 \cos \theta + 6 \sin \theta$$ The set of points \(A\) is defined by $$A = \left\{ z : 0 \leqslant \arg z \leqslant \frac { \pi } { 3 } \right\} \cap \{ z : | z - 4 - 3 \mathbf { i } | \leqslant 5 \}$$ (b) (i) Show, by shading on your Argand diagram, the set of points \(A\).
(ii) Find the exact area of the region defined by \(A\), giving your answer in simplest form.
OCR FP1 AS 2018 March Q4
6 marks Standard +0.8
4 Find, in exact form, the area of the region on an Argand diagram which represents the locus of points for which \(| z - 5 - 2 \mathrm { i } | \leqslant \sqrt { 32 }\) and \(\operatorname { Re } ( z ) \geqslant 9\).
Edexcel FP1 Q21
13 marks Standard +0.3
Given that \(z = -2\sqrt{2} + 2\sqrt{2}i\) and \(w = 1 - i\sqrt{3}\), find
  1. \(\left|\frac{z}{w}\right|\), [3]
  2. \(\arg \left( \frac{z}{w} \right)\). [3]
  1. On an Argand diagram, plot points \(A\), \(B\), \(C\) and \(D\) representing the complex numbers \(z\), \(w\), \(\left( \frac{z}{w} \right)\) and 4, respectively. [3]
  2. Show that \(\angle AOC = \angle DOB\). [2]
  3. Find the area of triangle \(AOC\). [2]
SPS SPS FM Pure 2022 June Q3
8 marks Standard +0.3
  1. Show on an Argand diagram the locus of points given by $$|z - 10 - 12i| = 8$$ [2] Set \(A\) is defined by $$A = \left\{z : 0 \leq \arg(z - 10 - 10i) \leq \frac{\pi}{2}\right\} \cap \{z : |z - 10 - 12i| < 8\}$$
  2. Shade the region defined by \(A\) on your Argand diagram. [2]
  3. Determine the area of the region defined by \(A\). [4]
SPS SPS FM 2023 January Q11
10 marks Challenging +1.2
\includegraphics{figure_11} Figure 1 shows an Argand diagram. The set \(P\) of points that lie within the shaded region including its boundaries, is defined by $$P = \{z \in \mathbb{C} : a \leq |z + b + ci| \leq d\}$$ where \(a\), \(b\), \(c\) and \(d\) are integers.
  1. Write down the values of \(a\), \(b\), \(c\) and \(d\). [3]
The set \(Q\) is defined by $$Q = \{z \in \mathbb{C} : a \leq |z + b + ci| \leq d\} \cap \{z \in \mathbb{C} : |z - i| \leq |z - 3i|\}$$
  1. Determine the exact area of the region defined by \(Q\), giving your answer in simplest form. [7]
SPS SPS FM 2023 February Q11
6 marks Challenging +1.2
Find, in exact form, the area of the region on an Argand diagram which represents the locus of points for which \(|z - 5 - 2i| \leq \sqrt{32}\) and Re (z) \(\geq\) 9. [6]
SPS SPS FM 2025 February Q7
6 marks Challenging +1.2
Find, in exact form, the area of the region on an Argand diagram which represents the locus of points for which \(|z - 5 - 2i| \leq \sqrt{32}\) and \(\text{Re}(z) \geq 9\). [6]
OCR Further Pure Core 2 2021 June Q4
7 marks Standard +0.8
In an Argand diagram the points representing the numbers \(2 + 3i\) and \(1 - i\) are two adjacent vertices of a square \(S\).
  1. Find the area of \(S\). [3]
  2. Find all the possible pairs of numbers represented by the other two vertices of \(S\). [4]