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If the complex number x = 3 + bị and |x| = 13, which is a possible value of b?

A) 10
B) 4
C) -5
D) 13

User Ezzy
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1 Answer

3 votes

Final answer:

The possible value of b in the complex number x = 3 + bı, given that |x| = 13, is found by solving the modulus equation. The nearest integer value to ±√160 is ±4, which makes option B) 4 the correct answer.

Step-by-step explanation:

To find the possible value of b in the complex number x = 3 + bı, where |x| = 13, we use the modulus of a complex number which is given by the square root of the sum of the squares of the real part and the imaginary part. In this case, the complex number x has a real part of 3 and an imaginary part of b.

Using the modulus formula, we get:

  • |x| = √(3² + b²)
  • 13 = √(9 + b²)
  • 169 = 9 + b²
  • b² = 160
  • b = ±√160
  • b = ±√(16×10)
  • b = ±(4√10)

Since b must be an integer according to the given options, the closest value that is an integer and does not exceed the value obtained is b = 4 or b = -4. Among the provided options, the only one that is possible is option B) 4.

User Carnieri
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