[For this exercise, starting fourth dimension write downward your answer, without using R. Then, depository fiscal establishment jibe your reply using R.]
Answers to the exercises are available here.
Exercise 1
If
M=matrix(c(1:10),nrow=5,ncol=2,
dimnames=list(c('a','b','c','d','e'),c('A','B')))
What is the value of:
M
Exercise 2
Consider the matrix
What is the value of:
M
,What is the value of:
M[1,]
M[,1]
M[3,2]
M['e','A']
Exercise 3
Consider the matrix
What is the value of:
N
N=matrix(c(1:9),nrow=3,ncol=3,
dimnames=list(c('a','b','c'),c('A','B','C')))
What is the value of:
diag(N)
Exercise 4
What is the value of:
Is matrix ?
diag(4,3,3)
Is matrix ?
Exercise 5
If
What is the value of:
M=matrix(c(1:9),3,3,byrow=T,
dimnames=list(c('a','b','c'),c('d','e','f')))
What is the value of:
rownames(M)
colnames(M)
Exercise 6
What is the value of:
upper.tri(M)
lower.tri(M)
lower.tri(M,diag=T)
Exercise 7
Consider 2 matrix,
What is the value of:
M,N
M=matrix(c(1:9),3,3,byrow=T)
N=matrix(c(1:9),3,3)
What is the value of:
M*N
Exercise 8
Consider 2 matrix,
What is the value of:
M,N
M=matrix(c(1:9),3,3,byrow=T)
N=matrix(c(1:9),3,3)
What is the value of:
M%*%N
Exercise 9
Consider 2 matrix,
M,N
M=matrix(c(1:9),3,3,byrow=T)
N=matrix(c(1:9),3,3)
What is the value of:
(M+N)^2
Exercise 10
Consider 2 matrix,
Consider 2 matrix,
M,N
M=matrix(c(1:9),3,3,byrow=T)
N=matrix(c(1:9),3,3)
What is the value of:
M/N
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Below are the solutions to these exercises on regular sequences.
#################### # # # Exercise 1 # # # #################### #If M=matrix(c(1:10),nrow=5,ncol=2,dimnames=list(c('a','b','c','d','e'),c('A','B'))) #What is the value of: M
## H5N1 B ## a 1 half-dozen ## b 2 seven ## c three 8 ## d four nine ## e v 10
#################### # # # Exercise 2 # # # #################### #Consider the matrix M, #What is the value of: M[1,]
## H5N1 B ## 1 half-dozen
M[,1]
## a b c d e ## 1 2 three four v
M[3,2]
## [1] 8
M['e','A']
## [1] v
#################### # # # Exercise three # # # #################### #Consider the matrix N N=matrix(c(1:9),nrow=3,ncol=3,dimnames=list(c('a','b','c'),c('A','B','C'))) #What is the value of: diag(N)
## [1] 1 v nine
#################### # # # Exercise four # # # #################### #What is the value of: diag(4,3,3)
## [,1] [,2] [,3] ## [1,] four 0 0 ## [2,] 0 four 0 ## [3,] 0 0 four
#Is matrix ? is.matrix(diag(4,3,3))
## [1] TRUE
#################### # # # Exercise v # # # #################### #If M=matrix(c(1:9),3,3,byrow=T,dimnames=list(c('a','b','c'),c('d','e','f'))) #What is the value of: rownames(M)
## [1] "a" "b" "c"
colnames(M)
## [1] "d" "e" "f"
#################### # # # Exercise half-dozen # # # #################### #What is the value of: upper.tri(M)
## [,1] [,2] [,3] ## [1,] FALSE TRUE TRUE ## [2,] FALSE FALSE TRUE ## [3,] FALSE FALSE FALSE
lower.tri(M)
## [,1] [,2] [,3] ## [1,] FALSE FALSE FALSE ## [2,] TRUE FALSE FALSE ## [3,] TRUE TRUE FALSE
lower.tri(M,diag=T)
## [,1] [,2] [,3] ## [1,] TRUE FALSE FALSE ## [2,] TRUE TRUE FALSE ## [3,] TRUE TRUE TRUE
#################### # # # Exercise seven # # # #################### #Consider 2 matrix, M,N M=matrix(c(1:9),3,3,byrow=T) N=matrix(c(1:9),3,3) #What is the value of: M*N
## [,1] [,2] [,3] ## [1,] 1 8 21 ## [2,] 8 25 48 ## [3,] 21 48 81
#################### # # # Exercise 8 # # # #################### #Consider 2 matrix, M,N M=matrix(c(1:9),3,3,byrow=T) N=matrix(c(1:9),3,3) #What is the value of: M%*%N
## [,1] [,2] [,3] ## [1,] xiv 32 l ## [2,] 32 77 122 ## [3,] l 122 194
#################### # # # Exercise nine # # # #################### #Consider 2 matrix,M,N M=matrix(c(1:9),3,3,byrow=T) N=matrix(c(1:9),3,3) #What is the value of: (M+N)^2
## [,1] [,2] [,3] ## [1,] four 36 100 ## [2,] 36 100 196 ## [3,] 100 196 324
#################### # # # Exercise 10 # # # #################### #Consider 2 matrix,M,N M=matrix(c(1:9),3,3,byrow=T) N=matrix(c(1:9),3,3) #What is the value of: M/N
## [,1] [,2] [,3] ## [1,] 1.000000 0.500000 0.4285714 ## [2,] 2.000000 1.000000 0.7500000 ## [3,] 2.333333 1.333333 1.0000000
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