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TS EAMCET · Maths · Complex Number

If the conjugate of \((x+i y)(1-2 i)\) is \((1+i)\), then

  1. A \(x+i y=1-i\)
  2. B \(x+i y=\frac{1-i}{1-2 i}\)
  3. C \(x-i y=\frac{1-i}{1+2 i}\)
  4. D \(x-i y=\frac{1-i}{1+i}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(x+i y=\frac{1-i}{1-2 i}\)

Step-by-step Solution

Detailed explanation

We have, Conjugate of \((x+i y)(1-2 i)\) is \(1+i\). i.e. \(\quad(x-i y)(1+2 i)=1+i\) \(\Rightarrow \quad x-i y=\frac{1+i}{1+2 i}\) Taking conjugate both sides, we get \[ x+i y=\frac{1-i}{1-2 i} \]