Provide an example:
1) A sequence with infinitely many terms equal to 1 and
infinitely many terms that are not equal to 1 that is
convergent.
2) A sequence that converges to 1 and has exactly one term equal
to 1.
3) A sequence that converges to 1, but all of its terms are
irrational numbers.
1.Prove that{2k+1:k∈N}∩{2k2 :k∈N}=∅.
2.Give two examples of ordered sets where the meaning of ” ≤ ”
is not the same as the one used with the set of real numbers R.
Prove that there exist infinitely many positive real numbers
r such that the equation 2x +
3y + 5z = r has no
solution (x,y,z) ∈ Q × Q × Q.
(Hint: Is the set S
= {2x + 3y +
5z : (x,y,z) ∈ Q × Q × Q}
countable?)