Ch. 5 - Systems and Matrices

Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook

Lial 13th Edition

Ch. 5 - Systems and Matrices

Problem 63

Chapter 6, Problem 63

Find each product, if possible. See Examples 5–7. <4x2 Matrix>

Verified step by step guidance

Step 1: Understand the problem. We need to find the product of a 4x2 matrix with another matrix. To multiply matrices, the number of columns in the first matrix must equal the number of rows in the second matrix.

Step 2: Identify the dimensions of the matrices. The given matrix is a 4x2 matrix, which means it has 4 rows and 2 columns.

Step 3: Determine the dimensions of the second matrix. To multiply with a 4x2 matrix, the second matrix must have 2 rows. The resulting product will have dimensions based on the outer dimensions of the matrices being multiplied.

Step 4: Set up the multiplication. If the second matrix is a 2xN matrix, the resulting product will be a 4xN matrix. Each element in the resulting matrix is found by taking the dot product of the corresponding row from the first matrix and the column from the second matrix.

Step 5: Perform the matrix multiplication. For each element in the resulting matrix, multiply corresponding elements from the row of the first matrix and the column of the second matrix, then sum these products.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Matrix Multiplication

Matrix multiplication involves taking two matrices and producing a new matrix by multiplying rows of the first matrix by columns of the second. The number of columns in the first matrix must equal the number of rows in the second matrix for multiplication to be possible. The resulting matrix's dimensions are determined by the number of rows from the first matrix and the number of columns from the second.

Dimensions of a Matrix

The dimensions of a matrix are defined by the number of rows and columns it contains, expressed as 'm x n' where 'm' is the number of rows and 'n' is the number of columns. Understanding the dimensions is crucial for determining compatibility for operations like addition and multiplication, as these operations have specific requirements regarding the sizes of the matrices involved.

Product of Matrices

The product of two matrices is a new matrix formed by the multiplication of the two original matrices. Each element in the resulting matrix is calculated as the sum of the products of corresponding elements from the rows of the first matrix and the columns of the second. This operation is fundamental in linear algebra and has applications in various fields, including computer graphics and systems of equations.

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Related Practice

Textbook Question

Solve each problem. Find all values of b such that the straight line 3x - y = b touches the circle x² + y² = 25 at only one point.

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Textbook Question

Find each product, if possible.

$[\begin{matrix} \sqrt{3} & 1 \\ 2 \sqrt{5} & 3 \sqrt{2} \end{matrix}] [\begin{matrix} \sqrt{3} & - \sqrt{6} \\ 4 \sqrt{3} & 0 \end{matrix}]$

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Textbook Question

Graph the solution set of each system of inequalities.

$y$\le$ x^3-x$

$y>-3$

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Textbook Question

Answer each question. Does the straight line 3x - 2y = 9 intersect the circle x² + y² = 25? (Hint: To find out, solve the system formed by these two equations.)

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Textbook Question

Use Cramer's rule to solve each system of equations. If D = 0, then use another method to determine the solution set. See Examples 5–7.

x + y = 4

2x - y = 2

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Textbook Question

Graph the solution set of each system of inequalities.

$y$\ge$3^{x}$

$y$\ge$2$

571

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