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Which of the Following is Correct for Any Two Complex Numbers Z1 and Z2? - Mathematics

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Question

Which of the following is correct for any two complex numbers z1 and z2?

 

Options

  • \[\left| z_1 z_2 \right| = \left| z_1 \right|\left| z_2 \right|\]

  • \[\arg\left( z_1 z_2 \right) = \arg\left( z_1 \right) \arg\left( z_2 \right)\]

  • \[\left| z_1 + z_2 \right| = \left| z_1 \right| + \left| z_2 \right|\]

  • \[\left| z_1 + z_2 \right| \geq \left| z_1 \right| + \left| z_2 \right|\]

MCQ
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Solution

Since, it is known that

\[\left| z_1 z_2 \right| = \left| z_1 \right|\left| z_2 \right|\]

\[\arg\left( z_1 z_2 \right) = \arg\left( z_1 \right) + \arg\left( z_2 \right)\] and

\[\left| z_1 + z_2 \right| \leq \left| z_1 \right| + \left| z_2 \right|\]

Hence, the correct option is (a).

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Chapter 13: Complex Numbers - Exercise 13.6 [Page 66]

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RD Sharma Mathematics [English] Class 11
Chapter 13 Complex Numbers
Exercise 13.6 | Q 42 | Page 66

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