Using field axioms, prove the following theorems:
(i) If x and y are non-zero real numbers, then xy does not equal
0
(ii) Let x and y be real numbers. Prove the following
statements
1. (-1)x = -x
2. (-x)y = -(xy)=x(-y)
3. (-x)(-y) = xy
(iii) Let a and b be real numbers, and x and y be non-zero real
numbers. Then a/x + b/y = (ay +bx)/(xy)
PROOFS:
1. State the prove The Density Theorem for Rational Numbers
2. Prove that irrational numbers are dense in the set of real numbers
3. Prove that rational numbers are countable
4. Prove that real numbers are uncountable
5. Prove that square root of 2 is irrational
what static equilibrium is. Give three examples of (non-trivial)
static equilibrium in the real world (e.g. a suspension bridge is
held up by several cables that apply forces and torques in various
directions, but both the net force and net torque are designed to
be zero as long as the load is sufficiently small).
Prove the following statements by using the definition of
convergence for sequences of
real numbers.
a) If {cn} is a sequence of real numbers and {cn} converges to 1
then {1/(cn+1)} converges to 1/2
b) If {an} and {bn} are sequences of real numbers and {an}
converges A and {bn} converges to B and B is not equal to 0 then
{an/bn} converges to A/B
Give examples of two non-value added activities that may be
found in each of the following organizations and
explain why.
(1) a university,
(2) a restaurant,
(3) a bicycle repair shop
Prove Corollary 4.22: A set of real numbers E is closed and
bounded if and only if every infinite subset of E has a point of
accumulation that belongs to E.
Use Theorem 4.21: [Bolzano-Weierstrass Property] A set of real
numbers is closed and bounded if and only if every sequence of
points chosen from the set has a subsequence that converges to a
point that belongs to E.
Must use Theorem 4.21 to prove Corollary 4.22 and there should...
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?)