NDA Math Mock Test 03 – Question 102

Question:

The number of non-zero integral solutions of the equation \(|1 – 2i|^x = 5^x\) is:

समीकरण \(|1 – 2i|^x = 5^x\) के गैर-शून्य पूर्णांक समाधानों की संख्या है:

Options:

  • Zero (No solution)
  • One
  • Two
  • Three
  • शून्य (कोई समाधान नहीं)
  • एक
  • दो
  • तीन

Correct Answer: a)

Explanation:

Evaluate the modulus of \(1 – 2i\):
\[|1 – 2i| = \sqrt{1^2 + (-2)^2} = \sqrt{1 + 4} = \sqrt{5} = 5^{1/2}\]
The equation becomes:
\[(5^{1/2})^x = 5^x \implies 5^{x/2} = 5^x \implies \frac{x}{2} = x \implies x = 0\]
The only integral solution is \(x = 0\).
Since the question asks for the number of non-zero integral solutions, there are none (zero).
Hence, the correct option is (a).

मापांक: \(|1 – 2i| = \sqrt{1 + 4} = 5^{1/2}\)।
समीकरण:
\[5^{x/2} = 5^x \implies \frac{x}{2} = x \implies x = 0\]
एकमात्र पूर्णांक हल \(x = 0\) है।
चूँकि गैर-शून्य (non-zero) पूर्णांक हल पूछा गया है, अतः ऐसे हलों की संख्या 0 (शून्य) है।
अतः सही विकल्प (a) है।

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