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JEE Mains · Maths · STD 11 - 4.1 complex nubers

Let \(S _{1}, S _{2}\) and \(S _{3}\) be three sets defined as \(S _{1}=\{ z \in C :| z -1| \leq \sqrt{2}\}\) ;  \(S _{2}=\{ z \in C : \operatorname{Re}((1- i ) z ) \geq 1\}\) ;  \(S _{3}=\{ z \in C : \operatorname{Im}( z ) \leq 1\}\) Then the set \(S _{1} \cap S _{2} \cap S _{3}\)

  1. A is a singleton
  2. B has exactly two elements
  3. C has infinitely many elements
  4. D has exactly three elements
Verified Solution

Answer & Solution

Correct Answer

(C) has infinitely many elements

Step-by-step Solution

Detailed explanation

For \(|z-1| \leq \sqrt{2}, z\) lies on and inside the circle of radius \(\sqrt{2}\) units and centre \((1,0) .\) For \(S _{2}\) Let \(z=x+i y\) Now, \((1-i)(z)=(1-i)(x+\) iy \()\) \(\operatorname{Re}((1-i) z)=x+y\) \(\Rightarrow x+y \geq 1\)…