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Express the Following Complex Number in the Standard Form a + I B: 3 − 4 I ( 4 − 2 I ) ( 1 + I ) - Mathematics

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Question

Express the following complex number in the standard form a + i b:

\[\frac{3 - 4i}{(4 - 2i)(1 + i)}\]

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Solution

\[\frac{3 - 4i}{\left( 4 - 2i \right)\left( 1 + i \right)}\]

\[ = \frac{3 - 4i}{4 + 2i - 2 i^2} \left( \because i^2 = - 1 \right)\]

\[ = \frac{3 - 4i}{6 + 2i}\]

\[ = \frac{3 - 4i}{6 + 2i} \times \frac{6 - 2i}{6 - 2i}\]

\[ = \frac{18 - 6i - 24i + 8 i^2}{36 - 4 i^2}\]

\[ = \frac{18 - 30i - 8}{36 + 4} \]

\[ = \frac{10 - 30i}{40}\]

\[ = \frac{1}{4} - \frac{3}{4}i\]

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Chapter 13: Complex Numbers - Exercise 13.2 [Page 31]

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RD Sharma Mathematics [English] Class 11
Chapter 13 Complex Numbers
Exercise 13.2 | Q 1.1 | Page 31

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