(Integration) Let
a,binR
with
g:[a,b]->Rga. Let g:[a,b]->R be decreasing. Prove that g is Riemann integerable.
425 For problems 1-5 you chose one and I chose one. For problem 6, one part is chosen at random. You will have a whiteboard available to demonstrate your argument, feel free to use pictures. (Completeness) Prove that
R
is complete using the tools from this class. (Compactness) Let
x,Y
be metric spaces. Let
Asubex
be nonempty and compact, let
f:A->Y
. Show that if
f
is continuous then
f(A)
is compact. (Connectedness) Let
x
a be metric space. Let
A,Bsubex
be nonempty and connected. Is
A\cup B
connected? Prove it or give a counterexample. (Counterexample must be specific!) (Differentiation) Let
a,binR
with
f:[a,b]->Rcin(a,b)cca,binRf:[a,b]->Rf^(')xin(a,b)f^(')a,binRg:[a,b]->RgRRA\cap Bf(x)=(1)/(x)f(1)=1,f(-1)=-1cf(c)=0cin(a,b)cca. Let g:[a,b]->R be decreasing. Prove that g is Riemann integerable.
Chosen at random.
(a) Give an example of a noncomplete subset of R and show why it is not complete. Be specific.
(b) Explain the min-max theorem. Then give an example of a bounded noncompact subset of R to for which the an min or max is not achieved.
(c) Is A\cap B connected? Prove it or give a counterexample. (Counterexample must be specific!)
(d) Explain why the function f(x)=(1)/(x) is continuous, f(1)=1,f(-1)=-1, yet there is no value c such that f(c)=0. Explain why this doesn't contradict the intermediate value theorem.
(e) Let cin(a,b). If a function is continuous at c it is differentiable at c. Prove it or give a counterexample. (Counterexample must be specific!)a. Let f:[a,b]->R be differentiable. Suppose that the left-hand limits and right-hand limits of f^(') exist at all xin(a,b). Prove that f^(') is continuous. (There are several cases, choose just one case, illustrate with a picture and an argument.)a. Let f:[a,b]->R. (One of the two.)
(a) Let cin(a,b). If a function is differentiable at c it is continuous at c. Prove it or give a counterexample. (Counterexample must be specific!)
(b) Let a,binR with a. Let f:[a,b]->R be differentiable. Suppose that the left-hand limits and right-hand limits of f^(') exist at all xin(a,b). Prove that f^(') is continuous. (There are several cases, choose just one case, illustrate with a picture and an argument.)