Math Problem Statement

Solve the equation (1 + i)x + 2u = v for x where:

u (1x3 matrix) = [8, 1+3i, 8 - 1] and v (1x3 matrix) = [4, 6 + 6i, 2i - 6]

x =

Solution

We are given the equation:

(1+i)x+2u=v(1 + i)x + 2u = v

Where:

  • u=[8,1+3i,81]u = [8, 1 + 3i, 8 - 1] (a 1×31 \times 3 matrix),
  • v=[4,6+6i,2i6]v = [4, 6 + 6i, 2i - 6] (a 1×31 \times 3 matrix),
  • xx is the unknown matrix we need to solve for.

Steps:

  1. Isolate xx:

    (1+i)x=v2u(1 + i)x = v - 2u

    So, we subtract 2u2u from vv:

    [ v - 2u = [4, 6 + 6i, 2i - 6] - 2 \times [8, 1 + 3i, 8 - 1] ]

  2. Multiply uu by 2:

    2u=[16,2+6i,162]2u = [16, 2 + 6i, 16 - 2]

    Now, subtract 2u2u from vv:

    [ v - 2u = [4, 6 + 6i, 2i - 6] - [16, 2 + 6i, 16 - 2] ]

  3. Perform the subtraction:

    v2u=[416,(6+6i)(2+6i),(2i6)(162)]v - 2u = [4 - 16, (6 + 6i) - (2 + 6i), (2i - 6) - (16 - 2)]

    Simplifying the components:

    v2u=[12,4+6i,2i616+2]v - 2u = [-12, 4 + 6i, 2i - 6 - 16 + 2]

    v2u=[12,4+6i,2i20]v - 2u = [-12, 4 + 6i, 2i - 20]

  4. Now, solve for xx:

    x=v2u1+ix = \frac{v - 2u}{1 + i}

    To divide by 1+i1 + i, multiply the numerator and denominator by the complex conjugate of 1+i1 + i, which is 1i1 - i:

    x=[12,4+6i,2i20]1+i×1i1ix = \frac{[-12, 4 + 6i, 2i - 20]}{1 + i} \times \frac{1 - i}{1 - i}

    Simplifying the denominator:

    (1+i)(1i)=12i2=1+1=2(1 + i)(1 - i) = 1^2 - i^2 = 1 + 1 = 2

    So:

    x=1i2×[12,4+6i,2i20]x = \frac{1 - i}{2} \times [-12, 4 + 6i, 2i - 20]

    Now, distribute 1i2\frac{1 - i}{2} across each element of the matrix:

    x=[(12)(1i)2,(4+6i)(1i)2,(2i20)(1i)2]x = \left[ \frac{(-12)(1 - i)}{2}, \frac{(4 + 6i)(1 - i)}{2}, \frac{(2i - 20)(1 - i)}{2} \right]

Let's compute each term.

First term:

(12)(1i)2=12+12i2=6+6i\frac{(-12)(1 - i)}{2} = \frac{-12 + 12i}{2} = -6 + 6i

Second term:

(4+6i)(1i)2\frac{(4 + 6i)(1 - i)}{2} Expand using distributive property:

= 4 - 4i + 6i - 6 = -2 + 2i$$ Now divide by 2: $$\frac{-2 + 2i}{2} = -1 + i$$ #### Third term: $$\frac{(2i - 20)(1 - i)}{2}$$ Expand using distributive property: $$(2i - 20)(1 - i) = 2i(1) - 2i(i) - 20(1) + 20(i) = 2i + 2 - 20 + 20i = -18 + 22i$$ Now divide by 2: $$\frac{-18 + 22i}{2} = -9 + 11i$$ ### Final result for $$x$$: $$x = [-6 + 6i, -1 + i, -9 + 11i]$$ --- Would you like more details or any clarifications? Here are some related questions: 1. How can we verify this result using matrix multiplication? 2. What happens if we change the values of $$u$$ and $$v$$? 3. How do complex conjugates help in dividing complex numbers? 4. How would the solution change if we had a $$2 \times 2$$ matrix instead? 5. What other matrix operations can we perform on $$u$$ and $$v$$? **Tip:** Always use the complex conjugate to simplify division by a complex number, as it eliminates the imaginary part in the denominator.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Matrix Operations
Complex Numbers
Solving Equations

Formulas

Matrix equation: (1 + i)x + 2u = v
Complex division using the conjugate
Matrix subtraction and multiplication

Theorems

Matrix operations
Complex conjugate theorem

Suitable Grade Level

Grades 11-12