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If Z1, Z2, Z3 Are Complex Numbers Such that | Z 1 | = | Z 2 | = | Z 3 | = ∣ ∣ ∣ 1 Z 1 + 1 Z 2 + 1 Z 3 ∣ ∣ ∣ = 1 Then Find the Value of | Z 1 + Z 2 + Z 3 | . - Mathematics

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Question

If z1z2z3 are complex numbers such that \[\left| z_1 \right| = \left| z_2 \right| = \left| z_3 \right| = \left| \frac{1}{z_1} + \frac{1}{z_2} + \frac{1}{z_3} \right| = 1\] then find the value of \[\left| z_1 + z_2 + z_3 \right|\] .

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Solution

\[\left| z_1 + z_2 + z_3 \right| = \left| \frac{z_1 \bar{{z_1}}}{\bar{{z_1}}} + \frac{z_2 \bar{{z_2}}}{\bar{{z_2}}} + \frac{z_3 \bar{{z_3}}}{\bar{{z_3}}} \right|\]

\[ = \left| \frac{\left| z_1 \right|^2}{\bar{{z_1}}} + \frac{\left| z_2 \right|^2}{\bar{{z_2}}} + \frac{\left| z_3 \right|^2}{\bar{{z_3}}} \right|\]

\[ = \left| \frac{1}{\bar{{z_1}}} + \frac{1}{\bar{{z_2}}} + \frac{1}{\bar{{z_3}}} \right| [ \because \left| z_1 \right| = \left| z_2 \right| = \left| z_3 \right| = 1]\]

\[ = \bar{\left| \frac{1}{z_1} + \frac{1}{z_2} + \frac{1}{z_3} \right|}\]

\[ = 1 \left[ \because \left| \frac{1}{z_1} + \frac{1}{z_2} + \frac{1}{z_3} \right| = 1 \right]\]

Thus, the value of \[\left| z_1 + z_2 + z_3 \right|\] is 1.

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Chapter 13: Complex Numbers - Exercise 13.2 [Page 33]

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RD Sharma Mathematics [English] Class 11
Chapter 13 Complex Numbers
Exercise 13.2 | Q 25 | Page 33

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