Verified answer

S(n) = 2/n = {2,1,2/3,1/2,2/5,1/3,2/7,...}

a)

is bounded above

its max is 2

b)

is bounded below

its inf is 0

(0 is inf and not min because 0 is not in S)

c)

is bounded because it is bounded above and below

consider the elements of S as points of x axis

they all lie in the interval [0,2], which is bounded

d)

it is positive

g)

it is strictly decreasing

s(n) > s(n+1), for any n ≥ 1

2/n > 2/(n + 1)

because, inverting

n/2 < (n + 1)/2

n < n + 1

which is true for any n