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Consider the region R in the Argand plan...

Consider the region `R` in the Argand plane described by the complex number. `Z` satisfying the inequalities `|Z-2| le |Z-4|`, `|Z-3| le |Z+3|`, `|Z-i| le |Z-3i|`, `|Z+i| le |Z+3i|`
Answer the followin questions :
The maximum value of `|Z|` for any `Z` in `R` is

A

`5`

B

`3`

C

`1`

D

`sqrt(13)`

Text Solution

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The correct Answer is:
To solve the problem, we need to analyze the inequalities given for the complex number \( Z \) in the Argand plane. Let's denote \( Z = x + iy \), where \( x \) and \( y \) are the real and imaginary parts of \( Z \), respectively. ### Step 1: Analyze the first inequality \( |Z - 2| \leq |Z - 4| \) This inequality can be rewritten as: \[ |Z - 2|^2 \leq |Z - 4|^2 \] Substituting \( Z = x + iy \): \[ |(x - 2) + iy|^2 \leq |(x - 4) + iy|^2 \] This expands to: \[ (x - 2)^2 + y^2 \leq (x - 4)^2 + y^2 \] Cancelling \( y^2 \) from both sides: \[ (x - 2)^2 \leq (x - 4)^2 \] Expanding both sides: \[ x^2 - 4x + 4 \leq x^2 - 8x + 16 \] Simplifying gives: \[ 4x \leq 12 \implies x \leq 3 \] ### Step 2: Analyze the second inequality \( |Z - 3| \leq |Z + 3| \) Rewriting this: \[ |Z - 3|^2 \leq |Z + 3|^2 \] Substituting \( Z = x + iy \): \[ |(x - 3) + iy|^2 \leq |(x + 3) + iy|^2 \] This expands to: \[ (x - 3)^2 + y^2 \leq (x + 3)^2 + y^2 \] Cancelling \( y^2 \) gives: \[ (x - 3)^2 \leq (x + 3)^2 \] Expanding both sides: \[ x^2 - 6x + 9 \leq x^2 + 6x + 9 \] Simplifying gives: \[ -12x \leq 0 \implies x \geq 0 \] ### Step 3: Analyze the third inequality \( |Z - i| \leq |Z - 3i| \) Rewriting this: \[ |Z - i|^2 \leq |Z - 3i|^2 \] Substituting \( Z = x + iy \): \[ |(x) + (y - 1)i|^2 \leq |(x) + (y - 3)i|^2 \] This expands to: \[ x^2 + (y - 1)^2 \leq x^2 + (y - 3)^2 \] Cancelling \( x^2 \) gives: \[ (y - 1)^2 \leq (y - 3)^2 \] Expanding both sides: \[ y^2 - 2y + 1 \leq y^2 - 6y + 9 \] Simplifying gives: \[ 4y \leq 8 \implies y \leq 2 \] ### Step 4: Analyze the fourth inequality \( |Z + i| \leq |Z + 3i| \) Rewriting this: \[ |Z + i|^2 \leq |Z + 3i|^2 \] Substituting \( Z = x + iy \): \[ |(x) + (y + 1)i|^2 \leq |(x) + (y + 3)i|^2 \] This expands to: \[ x^2 + (y + 1)^2 \leq x^2 + (y + 3)^2 \] Cancelling \( x^2 \) gives: \[ (y + 1)^2 \leq (y + 3)^2 \] Expanding both sides: \[ y^2 + 2y + 1 \leq y^2 + 6y + 9 \] Simplifying gives: \[ -4y \leq 8 \implies y \geq -2 \] ### Step 5: Combine the inequalities From the inequalities derived: 1. \( 0 \leq x \leq 3 \) 2. \( -2 \leq y \leq 2 \) This describes a rectangle in the Argand plane with vertices at \( (0, -2) \), \( (0, 2) \), \( (3, -2) \), and \( (3, 2) \). ### Step 6: Find the maximum value of \( |Z| \) The maximum modulus \( |Z| \) occurs at the vertex farthest from the origin, which is \( (3, 2) \): \[ |Z| = \sqrt{x^2 + y^2} = \sqrt{3^2 + 2^2} = \sqrt{9 + 4} = \sqrt{13} \] ### Final Answer: The maximum value of \( |Z| \) for any \( Z \) in \( R \) is \( \sqrt{13} \). ---

To solve the problem, we need to analyze the inequalities given for the complex number \( Z \) in the Argand plane. Let's denote \( Z = x + iy \), where \( x \) and \( y \) are the real and imaginary parts of \( Z \), respectively. ### Step 1: Analyze the first inequality \( |Z - 2| \leq |Z - 4| \) This inequality can be rewritten as: \[ |Z - 2|^2 \leq |Z - 4|^2 \] ...
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