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.)
6.(a) Show that if f : [a,b]→R is Riemann integrable and if m ≤
f (t) ≤ M holds
for all t in the subinterval [c,d] of [a,b], then
m(d −c) ≤ ∫cd f(t) dt ≤ M(d −c). (that is
supposed to be f integrated from c to d)
(b) Prove the fundamental theorem of calculus, in the form given in
the Introduction
to this book. (Hint: Use part (a) to estimate
F(x)−F(x0)/x−x0.)
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...