Math Problem Statement

Diketahui A = [3, -4; 2, 1], B = [-3, -2; -1, 5] dan C = [5, 4; -2, -1]. Tentukan A^T - 2B - 4C!

Solution

The problem asks you to calculate AT2B4CA^T - 2B - 4C, where the matrices AA, BB, and CC are provided as:

A=[3421],B=[3215],C=[5421]A = \begin{bmatrix} 3 & -4 \\ 2 & 1 \end{bmatrix}, \quad B = \begin{bmatrix} -3 & -2 \\ -1 & 5 \end{bmatrix}, \quad C = \begin{bmatrix} 5 & 4 \\ -2 & -1 \end{bmatrix}

Step 1: Find the transpose of matrix AA, denoted as ATA^T.

AT=[3241]A^T = \begin{bmatrix} 3 & 2 \\ -4 & 1 \end{bmatrix}

Step 2: Multiply matrix BB by 2.

2B=2×[3215]=[64210]2B = 2 \times \begin{bmatrix} -3 & -2 \\ -1 & 5 \end{bmatrix} = \begin{bmatrix} -6 & -4 \\ -2 & 10 \end{bmatrix}

Step 3: Multiply matrix CC by 4.

4C=4×[5421]=[201684]4C = 4 \times \begin{bmatrix} 5 & 4 \\ -2 & -1 \end{bmatrix} = \begin{bmatrix} 20 & 16 \\ -8 & -4 \end{bmatrix}

Step 4: Subtract 2B2B and 4C4C from ATA^T.

Now, calculate:

AT2B4C=[3241][64210][201684]A^T - 2B - 4C = \begin{bmatrix} 3 & 2 \\ -4 & 1 \end{bmatrix} - \begin{bmatrix} -6 & -4 \\ -2 & 10 \end{bmatrix} - \begin{bmatrix} 20 & 16 \\ -8 & -4 \end{bmatrix}

Perform the subtraction step by step:

  1. First, subtract 2B2B from ATA^T:

AT2B=[3241][64210]=[3+62+44+2110]=[9629]A^T - 2B = \begin{bmatrix} 3 & 2 \\ -4 & 1 \end{bmatrix} - \begin{bmatrix} -6 & -4 \\ -2 & 10 \end{bmatrix} = \begin{bmatrix} 3 + 6 & 2 + 4 \\ -4 + 2 & 1 - 10 \end{bmatrix} = \begin{bmatrix} 9 & 6 \\ -2 & -9 \end{bmatrix}

  1. Next, subtract 4C4C:

AT2B4C=[9629][201684]=[9206162(8)9(4)]=[111065]A^T - 2B - 4C = \begin{bmatrix} 9 & 6 \\ -2 & -9 \end{bmatrix} - \begin{bmatrix} 20 & 16 \\ -8 & -4 \end{bmatrix} = \begin{bmatrix} 9 - 20 & 6 - 16 \\ -2 - (-8) & -9 - (-4) \end{bmatrix} = \begin{bmatrix} -11 & -10 \\ 6 & -5 \end{bmatrix}

Final Answer:

AT2B4C=[111065]A^T - 2B - 4C = \begin{bmatrix} -11 & -10 \\ 6 & -5 \end{bmatrix}

Let me know if you'd like more details, or if you have any questions!

Related Questions:

  1. How do you find the determinant of matrix AA?
  2. What is the inverse of matrix BB, if it exists?
  3. How do you calculate the rank of matrix CC?
  4. Can you describe the geometric interpretation of matrix transposition?
  5. What are eigenvalues and eigenvectors, and how would you compute them for matrix AA?

Tip:

When subtracting or adding matrices, make sure both matrices are of the same dimension and perform element-wise operations to avoid errors.

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Math Problem Analysis

Mathematical Concepts

Matrix Operations
Matrix Transpose
Matrix Addition
Matrix Subtraction

Formulas

Transpose of a matrix A^T
Matrix Scalar Multiplication: k * A
Matrix Subtraction: A - B

Theorems

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Suitable Grade Level

College or Advanced High School (Linear Algebra)