Question

If $z=\frac{4}{1-i}$, then $\overline{z}$ is (where $\overline{z}$ is complex conjugate of z)

• A. $2(1+i)$
• B. $(1+i)$
• C. $\frac{2}{1-i}$
• D. $\frac{4i}{1+i}$

Answer 1

Answer: (A)

$2(1+i)$

$z=\frac{4}{1-i}\Rightarrow z=\frac{4}{1-i}\times \frac{1+i}{1+i}$
$=\frac{4(1+i)}{1^1-i^2}=2(1+i)$
$\therefore \overline{z}=\frac{2(1-i)\times (1+i)}{1+i}$
$=\frac{4}{1+i}$