4. Show that the set A = {fm,b : R → R | m does not...
4. Show that the set A = {fm,b : R → R | m does not
equal 0 and fm,b(x) = mx + b, m, b ∈ R} forms a group
under composition of functions. (The set A is called the set of
affine functions from R to R.)
Let A ⊂ R be a nonempty discrete set
a. Show that A is at most countable
b. Let f: A →R be any function, and let p ∈ A be any point. Show
that f is continuous at p
Recall that a set B is dense in R if an element of B can be
found between any two real numbers a < b. Take p∈Z and q∈N in
every case. It is given that the set of all rational numbers p/q
with 10|p| ≥ q is not dense in R.
Explain, using plain words (without a rigorous proof), why this is.
That is, present a general argument in plain
words. Does this set violate the Archimedean Property? If...
Suppose {a1,...,am} is a complete set of representatives for
Z/mZ. Show:
(i) If (b,m)=1, then{b*a1,...,b*am}is a complete set of
representatives.
(ii) If (b,m)> 1, then{b*a1,...,b*am}is not a
complete set of representatives.