《统计建模与R软件》练习答案-第2章

Exercise 1.

x=c(1,2,3)
y=c(4,5,6)
e=c(1,1,1)
z=2*x+y+e
print(z)
pn=crossprod(x,y)
pw=tcrossprod(x,y)
print(pn)
print(pw)


Exercise 2.

A=matrix(c(1:20), nrow=4, ncol=5)
print(A)

B=matrix(c(1:20), nrow=4, ncol=5, byrow=T)
print(B)

C=A+B
print(C)


E=A*B
print(E)
 

F=A[1:3, 1:3]
print(F)

G=B[1:4, -3]
print(G)

Exercise 3.

x=c(rep(1,5), rep(2,3), rep(3,4), rep(4,2))
print(x)

Exercise 4.

n=5
H=matrix(0, nrow=n, ncol=n)
print(H)
for(i in 1:n) {
  for(j in 1:n) {
    H[i,j]=1/(i+j-1)
  }
}
print(H)

H1=solve(H)
print(H1)

E=eigen(H)
p