Module # 6 Doing math in R part 2

Github Link: https://github.com/rayhankhan-svg/r-programming-assignments

R Code: 

# 1) Matrices A and B

A <- matrix(c(2,0,1,3), ncol=2)

B <- matrix(c(5,2,4,-1), ncol=2)

A

B

# a) A + B

A_plus_B <- A + B

A_plus_B

# b) A - B

A_minus_B <- A - B

A_minus_B

# 2) diag() matrix size 4 with diagonal values 4,1,2,3

D <- diag(c(4,1,2,3))

D

# 3) Generate the 5x5 matrix using diag()

M <- diag(3, 5)      # start with 3s on the diagonal

M[1, 2:5] <- 1       # first row (cols 2-5) become 1

M[2:5, 1] <- 2       # first column (rows 2-5) become 2

M

Output: 

> # 1) Matrices A and B

> A <- matrix(c(2,0,1,3), ncol=2)

> B <- matrix(c(5,2,4,-1), ncol=2)

> 

> A

     [,1] [,2]

[1,]    2    1

[2,]    0    3

> B

     [,1] [,2]

[1,]    5    4

[2,]    2   -1

> 

> # a) A + B

> A_plus_B <- A + B

> A_plus_B

     [,1] [,2]

[1,]    7    5

[2,]    2    2

> 

> # b) A - B

> A_minus_B <- A - B

> A_minus_B

     [,1] [,2]

[1,]   -3   -3

[2,]   -2    4

> 

> 

> # 2) diag() matrix size 4 with diagonal values 4,1,2,3

> D <- diag(c(4,1,2,3))

> D

     [,1] [,2] [,3] [,4]

[1,]    4    0    0    0

[2,]    0    1    0    0

[3,]    0    0    2    0

[4,]    0    0    0    3

> 

> 

> # 3) Generate the 5x5 matrix using diag()

> M <- diag(3, 5)      # start with 3s on the diagonal

> M[1, 2:5] <- 1       # first row (cols 2-5) become 1

> M[2:5, 1] <- 2       # first column (rows 2-5) become 2

> M

     [,1] [,2] [,3] [,4] [,5]

[1,]    3    1    1    1    1

[2,]    2    3    0    0    0

[3,]    2    0    3    0    0

[4,]    2    0    0    3    0

[5,]    2    0    0    0    3

>

Explanation: 

I made two 2x2 matrices, A and B, in R for Module #6, and then used fundamental matrix operations to get A + B and A - B. As long as the dimensions of the matrices are the same, R can add and remove them element by element. My A + B and A - B outputs were in line with the anticipated element-wise computations. I then created a 4x4 matrix with diagonal values of 4, 1, 2, and 3 using the diag() method. Lastly, I used diag() to create the necessary 5x5 matrix by first creating a diagonal matrix of 3s and then changing the first row and first column to fit the assignment's pattern. This demonstrated how diag() may be used to quickly create organized matrices and then modify particular rows and columns.