Math Problem Statement

Diketahui matriks A, B, dan C. Tentukan hasil dari (4B)C + 2C dan transpos matriks A.

Solution

Let's work through the problem step by step.

Given Matrices:

The matrices provided are: A=[301211],B=[4102],C=[142315]A = \begin{bmatrix} 3 & 0 \\ -1 & 2 \\ 1 & 1 \end{bmatrix}, \quad B = \begin{bmatrix} 4 & -1 \\ 0 & 2 \end{bmatrix}, \quad C = \begin{bmatrix} 1 & 4 & 2 \\ 3 & 1 & 5 \end{bmatrix}

Problem Statements:

  1. Determine 4BC+2C4B C + 2C.
  2. Find the transpose of matrix AA.

Step-by-Step Solution:

1. Compute 4B4B

To find 4B4B, we multiply each element in matrix BB by 4: 4B=4×[4102]=[16408]4B = 4 \times \begin{bmatrix} 4 & -1 \\ 0 & 2 \end{bmatrix} = \begin{bmatrix} 16 & -4 \\ 0 & 8 \end{bmatrix}

2. Compute 4BC4B C

Next, we calculate the product of 4B4B and CC. The resulting matrix from this multiplication will have dimensions 2×32 \times 3 because 4B4B is 2×22 \times 2 and CC is 2×32 \times 3.

4BC=[16408][142315]4B C = \begin{bmatrix} 16 & -4 \\ 0 & 8 \end{bmatrix} \begin{bmatrix} 1 & 4 & 2 \\ 3 & 1 & 5 \end{bmatrix}

Let's calculate each element:

  • First row, first column: 16×1+(4)×3=1612=416 \times 1 + (-4) \times 3 = 16 - 12 = 4

  • First row, second column: 16×4+(4)×1=644=6016 \times 4 + (-4) \times 1 = 64 - 4 = 60

  • First row, third column: 16×2+(4)×5=3220=1216 \times 2 + (-4) \times 5 = 32 - 20 = 12

  • Second row, first column: 0×1+8×3=0+24=240 \times 1 + 8 \times 3 = 0 + 24 = 24

  • Second row, second column: 0×4+8×1=0+8=80 \times 4 + 8 \times 1 = 0 + 8 = 8

  • Second row, third column: 0×2+8×5=0+40=400 \times 2 + 8 \times 5 = 0 + 40 = 40

So, 4BC=[4601224840]4B C = \begin{bmatrix} 4 & 60 & 12 \\ 24 & 8 & 40 \end{bmatrix}

3. Compute 2C2C

Now, we find 2C2C by multiplying each element in CC by 2: 2C=2×[142315]=[2846210]2C = 2 \times \begin{bmatrix} 1 & 4 & 2 \\ 3 & 1 & 5 \end{bmatrix} = \begin{bmatrix} 2 & 8 & 4 \\ 6 & 2 & 10 \end{bmatrix}

4. Compute 4BC+2C4B C + 2C

Now, we add 4BC4B C and 2C2C element-wise: 4BC+2C=[4601224840]+[2846210]=[66816301050]4B C + 2C = \begin{bmatrix} 4 & 60 & 12 \\ 24 & 8 & 40 \end{bmatrix} + \begin{bmatrix} 2 & 8 & 4 \\ 6 & 2 & 10 \end{bmatrix} = \begin{bmatrix} 6 & 68 & 16 \\ 30 & 10 & 50 \end{bmatrix}

So, 4BC+2C=[66816301050]4B C + 2C = \begin{bmatrix} 6 & 68 & 16 \\ 30 & 10 & 50 \end{bmatrix}

5. Transpose of Matrix AA

The transpose of matrix AA, denoted as ATA^T, is obtained by swapping its rows and columns: A=[301211]AT=[311021]A = \begin{bmatrix} 3 & 0 \\ -1 & 2 \\ 1 & 1 \end{bmatrix} \Rightarrow A^T = \begin{bmatrix} 3 & -1 & 1 \\ 0 & 2 & 1 \end{bmatrix}

Final Answers:

  1. 4BC+2C=[66816301050]4B C + 2C = \begin{bmatrix} 6 & 68 & 16 \\ 30 & 10 & 50 \end{bmatrix}
  2. The transpose of AA, AT=[311021]A^T = \begin{bmatrix} 3 & -1 & 1 \\ 0 & 2 & 1 \end{bmatrix}

Would you like any further details on these steps, or have any questions?

Additional Related Questions:

  1. How do you perform matrix multiplication in general?
  2. What are the properties of matrix transposition?
  3. How does scalar multiplication work in matrices?
  4. Can we generalize this process for any arbitrary matrices BB and CC?
  5. How is matrix addition different from matrix multiplication?

Tip:

When performing matrix multiplication, always check the dimensions first to ensure compatibility.

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Math Problem Analysis

Mathematical Concepts

Matrix Multiplication
Scalar Multiplication
Matrix Addition
Matrix Transposition

Formulas

(kB) * C for scalar multiplication of matrix B and subsequent matrix multiplication with C
(kC) for scalar multiplication of matrix C
Matrix Addition for combining two matrices
Transpose of a Matrix

Theorems

Properties of Matrix Multiplication
Properties of Matrix Addition
Properties of Transpose

Suitable Grade Level

Grades 10-12