Find the real part of the complex number z = 4(cos(π/3) + i sin(π/3)).

Practice Questions

Q1
Find the real part of the complex number z = 4(cos(π/3) + i sin(π/3)).
  1. 2
  2. 4
  3. 3
  4. 1

Questions & Step-by-Step Solutions

Find the real part of the complex number z = 4(cos(π/3) + i sin(π/3)).
Correct Answer: 2
  • Step 1: Identify the complex number z given in the question, which is z = 4(cos(π/3) + i sin(π/3)).
  • Step 2: Recognize that the real part of a complex number in the form a(cos(θ) + i sin(θ)) is given by a * cos(θ).
  • Step 3: In this case, a = 4 and θ = π/3.
  • Step 4: Calculate cos(π/3). The value of cos(π/3) is 1/2.
  • Step 5: Multiply the value of a (which is 4) by cos(π/3): 4 * (1/2).
  • Step 6: Perform the multiplication: 4 * (1/2) = 2.
  • Step 7: Conclude that the real part of the complex number z is 2.
  • Complex Numbers – Understanding the representation of complex numbers in polar form and how to extract real and imaginary parts.
  • Trigonometric Functions – Knowledge of the values of trigonometric functions, specifically cosine and sine, at standard angles.
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