Questions
Real Analysis: Prove a subset of the Reals is compact if and only if it is...

Real Analysis: Prove a subset of the Reals is compact if and only if it is closed and bounded. In other words, the set of reals satisfies the Heine-Borel property.

In: Advanced Math

Soundex produces x Model A radios and y Model B radios. Model A requires 15 min...

Soundex produces x Model A radios and y Model B radios. Model A requires 15 min of work on Assembly Line I and 10 min of work on Assembly Line II. Model B requires 10 min of work on Assembly Line I and 12 min of work on Assembly Line II. At most, 25 labor-hours of assembly time on Line I and 22 labor-hours of assembly time on Line II are available each day. It is anticipated that Soundex will realize a profit of $15 on model A and $12 on model B. How many clock radios of each model should be produced each day in order to maximize Soundex's profit?

In: Advanced Math

Prove by induction: 1 + 1/4 + 1/9 +⋯+ 1/?^2 < 2 − 1/?, for all...

Prove by induction:

1 + 1/4 + 1/9 +⋯+ 1/?^2 < 2 − 1/?,

for all integers ?>1

In: Advanced Math

The table shows the estimated percentage P of the population of a certain country that are...

The table shows the estimated percentage P of the population of a certain country that are mobile-phone subscribers. (End of year estimates are given.)

Year 1997 1999 2001 2003 2005 2007
P 2.1 8.2 15.7 25 45.7 62.5


(c) Estimate the instantaneous rate of growth in 2003 by sketching a graph of P and measuring the slope of a tangent. (Sketch your graph so that it is a smooth curve through the points, and so that the tangent line has an x-intercept of 1999.3 and passing through the point

(2006, 46.6).  Round your answer to two decimal places.)

For part, c use the two points that are on the tangent line to determine the slope, which is the instantaneous rate of change.
.........................................  percentage points per year

In: Advanced Math

y"+y'-6y=1 1. general solution of corresponding homogenous equation 2. particular solution 3.solution of initial value problem...

y"+y'-6y=1

1. general solution of corresponding homogenous equation

2. particular solution

3.solution of initial value problem with initial conditions y(0)=y'(0)=0

In: Advanced Math

Suppose x,y ∈ R and assume that x < y. Show that for all z ∈...

Suppose x,y ∈ R and assume that x < y. Show that for all z ∈ (x,y), there exists α ∈ (0,1) so that αx+(1−α)y = z. Now, also prove that a set X ⊆ R is convex if and only if the set X satisfies the property that for all x,y ∈ X, with x < y, for all z ∈ (x,y), z ∈ X.

In: Advanced Math

Express the equation of the plane in explicit form a. d = [1, -3, -5]; e...

Express the equation of the plane in explicit form
a. d = [1, -3, -5]; e = [-2, 1, -1] and f = [5, -1, -3] Express the equation of the plane through d, e, and f explicitly
b. d = [-1, 7, -6]; e = [2, -1, 3] and f = [4, -2, 9] Express the equation of the plane through d, e, and f explicitly

In: Advanced Math

Let A = 2 0 1 0 2 0 1 0 2 and eigenvalue λ1 =...

Let A =

2 0 1
0 2 0
1 0 2

and eigenvalue λ1 = 3 and associated eigenvector v(1) = (1, 0, 1)t . Find the second dominant eigenvalue λ2 (or the approximation to λ2) by the Wielandt Dflation method

In: Advanced Math

1. Use Euler's method with step size 0.50.5 to compute the approximate yy-values y1≈y(0.5), y2≈y(1),y3≈y(1.5), and...

1.

Use Euler's method with step size 0.50.5 to compute the approximate yy-values y1≈y(0.5), y2≈y(1),y3≈y(1.5), and y4≈y(2) of the solution of the initial-value problem

y′=1+3x−2y,   y(0)=2.

y1=

y2=

y3=

y4=

2.  

Consider the differential equation dy/dx=6x, with initial condition y(0)=3

A. Use Euler's method with two steps to estimate y when x=1:

y(1)≈ (Be sure not to round your calculations at each step!)

Now use four steps:
y(1)≈

B. What is the solution to this differential equation (with the given initial condition)?
y=

C. What is the magnitude of the error in the two Euler approximations you found?
Magnitude of error in Euler with 2 steps =

Magnitude of error in Euler with 4 steps =

D. By what factor should the error in these approximations change (that is, the error with two steps should be what number times the error with four)?
factor =

(How close to this is the result you obtained above?)

In: Advanced Math

Let u and v be vectors in R3. Consider the following statements.T or F (1) |u ...

Let u and v be vectors in R3. Consider the following statements.T or F

(1) |u·v|  ≤  ||u|| + ||v||
(2) If  au + bv = cu + dv then  a  =  c  and  b  =  d.

(3) ||u + v||2  =  ||u||2 + ||v||2 + 2(u·v)

Let u, v, and w be vectors in R3. T or F.

(1) u·v − ||u||
(2) (u·v) × w
(3) || ( ||u|| projvu ) ||

In: Advanced Math

Let a < c < b, and let f be defined on [a,b]. Show that f...

Let a < c < b, and let f be defined on [a,b]. Show that f ∈ R[a,b] if and only if f ∈ R[a, c] and f ∈ R[c, b]. Moreover, Integral a,b f = integral a,c f + integral c,b f .

In: Advanced Math

A vector y  =  [R(t)  F(t)]T describes the populations of some rabbits R(t) and foxes F(t). The...

A vector y  =  [R(t)  F(t)]T describes the populations of some rabbits R(t) and foxes F(t). The populations obey the system of differential equations given by y′  =  Ay where

A  = 

[−2

15]
[−2 9 ]


The rabbit population begins at 6000. If we want the rabbit population to grow as a simple exponential of the form R(t)  =  R0e3t  with no other terms, how many foxes are needed at time t  =  0?
(Note that the eigenvalues of A are λ  = 3 and 4.)

In: Advanced Math

The weighted voting systems for the voters A, B, C, ... are given in the form...

The weighted voting systems for the voters A, B, C, ... are given in the form q: w1, w2, w3, w4, ..., wn . The weight of voter A is w1, the weight of voter B is w2, the weight of voter C is w3, and so on. Calculate, if possible, the Banzhaf power index for each voter. Round to the nearest hundredth. (If not possible, enter IMPOSSIBLE.) {82: 53, 36, 24, 18} BPI(A) = BPI(B) = BPI(C) = BPI(D) =

In: Advanced Math

Graph Theory: Let S be a set of three pairwise-nonadjacent edges in a 3-connected graph G....

Graph Theory: Let S be a set of three pairwise-nonadjacent edges in a 3-connected graph G. Show that there is a cycle in G containing all three edges of S unless S is an edge-cut of G

In: Advanced Math

Let En be the subspace of V (n, 2) consisting of all vectros of even weight....

Let En be the subspace of V (n, 2) consisting of all vectros of even weight.

(a) What are the parameters [n, k, d] of En.

(b) Write down a generator matrix for En in standard form

In: Advanced Math