NCERT Class XI Mathematics - Complex Numbers and Quadratic Equations - Solutions
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Question : 44
Total: 52
Let z 1 = 2 - i , z 2 = - 2 + i. Find
(i) Re(
) , (ii) Im (
)
(i) Re
Solution:
We have, z 1 = 2 - i , $z_2 = - 2 + i
(i)z 1 z 2 = ( 2 − i ) ( − 2 + i ) = − 4 + 2 i + 2 i − i^2$ = - 4 + 1 + 4i = - 3 + 4i
Also ,
= 2 + i
∴
=
=
×
=
=
= −
+
i
∴ Re(
) = -
(ii)z 1
= (2 - i) (2 + i) = 4 + 1 = 5
Now ,
=
=
+ 0i ⇒ Im (
) = 0
(i)
Also ,
∴
=
∴ Re
(ii)
Now ,
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