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For any complex number, if |Z| = 1, then the value of \(2(Z\ +\ \bar{Z})\ -\ 2(\frac{1}{Z}\ +\ \frac{1}{\bar{Z}})\) will be1. 12. 03. -14. 2 |
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Answer» Correct Answer - Option 2 : 0 Concept: Properties of |Z|: If Z = x + iy is a complex number then the following properties are applicable for |Z|. 1. \(|Z|\ =\ |\bar{Z}|\) 2. \(|z|^2 \ =\ Z̅{Z}\) 3. \(|\overline{z_1\ +\ z_2}|\ =\ |\bar{Z_1}\ +\ \bar{Z_2}|\) Calculation: Given that, |Z| = 1 ⇒ |Z|2 = 1 ⇒ Z Z̅ = 1 (∵ \(|z|^2 \ =\ Z̅{Z}\)) \(⇒ Z = \frac{1}{\bar{Z}}\) ----(1) Therefore, the value of \(2(Z\ +\ \bar{Z})\ -\ 2(\frac{1}{Z}\ +\ \frac{1}{\bar{Z}})\) = \(2(Z\ -\ \frac{1}{\bar{Z}})\ -\ 2(\ \bar{Z}\ -\ \frac{1}{Z})\) But, from equation (1) \( Z = \frac{1}{\bar{Z}}\) ⇒ \(2(Z\ -\ \frac{1}{\bar{Z}})\ -\ 2(\ \bar{Z}\ -\ \frac{1}{Z})\ =\ 0\) Hence, option 2 is correct. |
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