Matrix multiplication (%*%) in R Programming - Mini Project: Build & Apply

Matrix multiplication (%*%)

📖 Scenario: You work in a small company that needs to multiply two matrices to combine data from different departments. You will use R programming to do this.

🎯 Goal: Build a simple R program that multiplies two matrices using the matrix multiplication operator %*%.

📋 What You'll Learn

Create two matrices with exact values

Create a variable to store the result of matrix multiplication

Use the %*% operator to multiply the matrices

Print the resulting matrix

💡 Why This Matters

🌍 Real World

Matrix multiplication is used in data analysis, computer graphics, and scientific computing to combine data and transform information.

💼 Career

Understanding matrix multiplication is important for jobs in data science, machine learning, and software development where matrix operations are common.

1

Create two matrices

Create a matrix called matrix_a with values 1, 2, 3, 4 arranged in 2 rows and 2 columns, and a matrix called matrix_b with values 5, 6, 7, 8 arranged in 2 rows and 2 columns.

R Programming

# Create matrix_a and matrix_b with the exact values and dimensions
# Your code here

Need a hint?

Use the matrix() function with c() to create matrices. Specify nrow = 2 and ncol = 2.

2

Create a variable for the result

Create a variable called result to store the product of matrix_a and matrix_b.

R Programming

matrix_a <- matrix(c(1, 2, 3, 4), nrow = 2, ncol = 2, byrow = TRUE)
matrix_b <- matrix(c(5, 6, 7, 8), nrow = 2, ncol = 2, byrow = TRUE)
# Create variable result to hold multiplication output
# Your code here

Need a hint?

Just create the variable result first. You will assign the multiplication in the next step.

3

Multiply the matrices

Assign to result the product of matrix_a and matrix_b using the matrix multiplication operator %*%.

R Programming

matrix_a <- matrix(c(1, 2, 3, 4), nrow = 2, ncol = 2, byrow = TRUE)
matrix_b <- matrix(c(5, 6, 7, 8), nrow = 2, ncol = 2, byrow = TRUE)
result <- NULL
# Multiply matrix_a and matrix_b using %*% and assign to result
# Your code here

Need a hint?

Use %*% between matrix_a and matrix_b to multiply.

4

Print the result

Print the variable result to display the product matrix.

R Programming

matrix_a <- matrix(c(1, 2, 3, 4), nrow = 2, ncol = 2, byrow = TRUE)
matrix_b <- matrix(c(5, 6, 7, 8), nrow = 2, ncol = 2, byrow = TRUE)
result <- matrix_a %*% matrix_b
# Print the result matrix
# Your code here

Need a hint?

Use print(result) to show the matrix.