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AP EAMCET · Maths · Complex Number

If \(z=x+i y\) and \(x^2+y^2=1\), then \(\frac{1+x+i y}{1+x-i y}=\)

  1. A \(\bar{z}\)
  2. B z
  3. C \(z+1\)
  4. D \(z-1\)
Verified Solution

Answer & Solution

Correct Answer

(B) z

Step-by-step Solution

Detailed explanation

\(\frac{1+x+i y}{1+x-i y} = \frac{1+z}{1+\bar{z}}\) Since \(x^2+y^2=1\), \(|z|^2=1 \Rightarrow z\bar{z}=1 \Rightarrow \bar{z}=\frac{1}{z}\) \(\frac{1+z}{1+\frac{1}{z}} = \frac{1+z}{\frac{z+1}{z}}\) \((1+z) \cdot \frac{z}{z+1} = z\)