Question:medium

For all complex numbers z of the form 1 + i$\alpha$, $\alpha$ $\epsilon$ R, if z = x + iy, then :

Updated On: Apr 2, 2026
  • $y^2 - 4x + 2 = 0$
  • $y^2 + 4x - 4 = 0$
  • $y^2 - 4x + 4 = 0$
  • $y^2 + 4x + 2 = 0$
Show Solution

The Correct Option is B

Solution and Explanation

To solve this problem, we need to analyze the given information and derive the equation that satisfies the complex number condition.

  1. We have complex numbers of the form \( z = 1 + i\alpha \), where \( \alpha \in \mathbb{R} \).
  2. The complex number is expressed in the form \( z = x + iy \), where \( x \) and \( y \) are real numbers.
  3. By comparing the two forms of \( z \), we have \( x = 1 \) and \( y = \alpha \).
  4. We need to find a relationship involving \( x \) and \( y \) that matches one of the given options.
  5. The problem provides four potential relationships. To identify the correct one, we substitute \( x = 1 \) into each option and simplify:
  • Option 1: \( y^2 - 4x + 2 = 0 \)
    • Substituting: \( y^2 - 4(1) + 2 = y^2 - 4 + 2 = y^2 - 2 = 0 \)
    • This simplifies to \( y^2 = 2 \). This is not a general relationship involving \( y \).
  • Option 2: \( y^2 + 4x - 4 = 0 \)
    • Substituting: \( y^2 + 4(1) - 4 = y^2 + 4 - 4 = y^2 = 0 \)
    • This simplifies correctly since for \( y = \alpha \), which implies \( \alpha^2 = 0 \), is universally true because \( \alpha \) can be zero.
  • Option 3: \( y^2 - 4x + 4 = 0 \)
    • Substituting: \( y^2 - 4(1) + 4 = y^2 - 4 + 4 = y^2 = 0 \)
    • This condition is too strict, requiring \( y = 0 \), which is not applicable generally.
  • Option 4: \( y^2 + 4x + 2 = 0 \)
    • Substituting: \( y^2 + 4(1) + 2 = y^2 + 4 + 2 = y^2 + 6 = 0 \)
    • This condition requires \( y^2 = -6 \), which is not possible for real \( y \).

The only equation that accounts for the basic composition of the number in general without imposing impossible conditions is:

The correct answer is \( y^2 + 4x - 4 = 0 \).

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