Math Problem Statement

Let z

1.25 e 0.61 i and w

3.66 e − 2.31 i

Calculate z w .

Solution

To calculate z×wz \times w, we need to use the properties of multiplying complex numbers in polar form. Given:

z=1.25e0.61i,w=3.66e2.31iz = 1.25 e^{0.61 i}, \quad w = 3.66 e^{-2.31 i}

The multiplication of two complex numbers in polar form is given by the rule:

z×w=r1r2ei(θ1+θ2)z \times w = r_1 r_2 e^{i(\theta_1 + \theta_2)}

Where:

  • r1r_1 and r2r_2 are the magnitudes of zz and ww, respectively.
  • θ1\theta_1 and θ2\theta_2 are the angles of zz and ww, respectively.

Step 1: Multiply the magnitudes

r1=1.25,r2=3.66r_1 = 1.25, \quad r_2 = 3.66 r1×r2=1.25×3.66=4.575r_1 \times r_2 = 1.25 \times 3.66 = 4.575

Step 2: Add the angles

θ1=0.61,θ2=2.31\theta_1 = 0.61, \quad \theta_2 = -2.31 θ1+θ2=0.61+(2.31)=1.70\theta_1 + \theta_2 = 0.61 + (-2.31) = -1.70

Step 3: Write the product

z×w=4.575e1.70iz \times w = 4.575 e^{-1.70 i}

This is the product of zz and ww in polar form. You can also convert it back to rectangular (Cartesian) form if needed.

Would you like further details, such as converting to rectangular form or visualization?


Here are 5 related questions:

  1. How do you convert polar form of complex numbers to rectangular form?
  2. What are the properties of multiplying complex numbers in polar form?
  3. How can you divide two complex numbers in polar form?
  4. What is the physical significance of the argument of a complex number?
  5. How can you plot complex numbers in polar and Cartesian coordinates?

Tip: When multiplying complex numbers in polar form, always multiply the magnitudes and add the arguments (angles).

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Math Problem Analysis

Mathematical Concepts

Complex Numbers
Polar Form
Multiplication of Complex Numbers

Formulas

Multiplication of complex numbers in polar form: z × w = r₁ r₂ e^{i(θ₁ + θ₂)}

Theorems

Multiplication of Complex Numbers in Polar Form

Suitable Grade Level

Grades 11-12