Question:
If $\frac{(1+i)^{2}}{2-i}=x+i y$, find $x+y$
Solution:
$\frac{(1+i)^{2}}{2-i}=\frac{1^{2}+i^{2}+2 i}{2-i}$
$=\frac{1-1+2 i}{2-i} \quad\left[\because i^{2}=-1\right]$
$=\frac{2 i}{2-1} \times \frac{2+i}{2+i}$
$=\frac{2 i(2+i)}{2^{2}-i^{2}}$
$=\frac{4 i+2 i^{2}}{4+1} \quad \because i^{2}=-1 \mid$
$=\frac{4 i-2}{5}$
$=\frac{-2}{5}+\frac{4}{5} i$ ....(1)
It is given that,
$\frac{(1+i)^{2}}{2-i}=x+i y$
$\Rightarrow-\frac{2}{5}+\frac{4}{5} i=x+i y$ $[\operatorname{From}(1)]$
$\Rightarrow x=-\frac{2}{5}$ and $y=\frac{4}{5}$
$\therefore x+y=\frac{-2}{5}+\frac{4}{5}$
$=\frac{2}{5}$
Thus, $x+y=\frac{2}{5}$.