150k views
2 votes
1/(2+i)²

Solve this question....​

1 Answer

2 votes


\large\underline{\sf{Solution-}}

Given complex number is


\rm \longmapsto\:\frac{1}{ {(2 + i)}^(2) }


\rm \:  =  \: \frac{1}{4 + {i}^(2) + 2 * 2 * i}


\rm \:  =  \: (1)/(4 - 1 + 4i)


\rm \:  =  \: (1)/(3+ 4i)


\rm \:  =  \: (1)/(3+ 4i) * (3 - 4i)/(3 - 4i)


\rm \:  =  \: \frac{3 - 4i}{ {3}^(2) - {(4i)}^(2) }


\rm \:  =  \: \frac{3 - 4i}{9 -16 {i}^(2) }

We know,


\rm \longmapsto\:\tt{ {i}^(2) \: = \: - \: 1 \: } \\

So, using this, we get


\rm \:  =  \: (3 - 4i)/(9 -16( - 1))


\rm \:  =  \: (3 - 4i)/(9 + 16)


\rm \:  =  \: (3 - 4i)/(25)


\rm \:  =  \: (3)/(25) - (4)/(25)i

User Nad
by
4.1k points