Find the finite-difference solution of the heat-conduction
problem
PDE: ut = uxx 0 < x < 1, 0 < t < 1
BCs:
⇢
u(0, t) = 0
ux(1, t) = 0
0 < t < 1
IC: u(x, 0) = sin(pi x) 0 x 1
for t = 0.005, 0.010, 0.015 by the explicit method. Assume
In: Advanced Math
Explain Polya's Theorem and the basic ideas in the proof.
In: Advanced Math
The numbers used in the Trust Funds Model from this lesson are, of course, just estimates. Let’s investigate what happens if these estimates are off by 10%. To do so, answer the following questions:
Using a starting value of $3 trillion in the trust funds in 2032, with an annual rate of decline of 8.7%, how much money will be in the funds in 2040? The answer is 1448
Now let us assume the starting value of the funds was 10% less and the rate of decline was 10% greater than was estimated in the lesson. What is the estimated value of the trust funds in 2040? I need help with this specific question only. Thanks
In: Advanced Math
Exhibit L.1 reports the multivariate odds ratios comparing each category to women who never had an induced abortion and had at least one pregnancy. Researchers were able to interview 845 out of 1,011 (83.5 percent) of the eligible cases and 961 out of 1,239 (78 per- cent) of the eligible controls. Of the cases, only 689 (81.5 percent) had complete information on abortion history, compared to 781 (81.3 per- cent) of the eligible controls.
Abortion History |
Cases |
Controls |
Crude OR2 |
Multivariate OR (95% CI)3 |
Ever had abortion |
210 |
201 |
1.5 (1.2–1.9) |
|
1 abortion only |
150 |
142 |
1.5 (1.1–2.0) |
|
2+ abortions |
60 |
59 |
1.6 (1.0–2.4) |
|
Age at first abortion |
||||
<18 |
20 |
15 |
2.5 (1.1–5.7) |
|
18–19 |
34 |
36 |
1.7 (1.0–3.0) |
|
20–29 |
115 |
123 |
1.3 (1.0–1.7) |
|
30+ |
41 |
27 |
2.1 (1.2–3.5) |
|
Timing of first abortion |
||||
Before 1st birth |
69 |
76 |
1.4 (1.0–2.0) |
|
After 1st birth |
74 |
63 |
1.5 (1.0–2.2) |
|
Never gave birth |
67 |
62 |
1.7 (1.2–2.6) |
|
Never had abortion |
479 |
580 |
–– |
|
Never had an abortion and at least one pregnancy1 |
466 |
564 |
–– |
Note: 1. Estimated from the data. 2. Multivariate OR adjusts for age, family history of breast cancer, religion, age at first pregnancy. 3. Both crude and multivariate odds ratio estimates risk relative to women with a least one pregnancy who never had an induced abortion. Source: Daling et al. (1994).
Calculate the crude odds ratios for each of the abortion history strata in Exhibit L.1. What is the overall increased risk of abortion after adjusting for several covariates?
In: Advanced Math
Use the Chain Rule to find the indicated partial derivatives. N = p + q p + r , p = u + vw, q = v + uw, r = w + uv; ∂N ∂u , ∂N ∂v , ∂N ∂w when u = 4, v = 2, w = 8
In: Advanced Math
Let x = (1,1) and y = (3,1).
1. Find an explicit hyperbolic isometry f that sends the semicircle that x and y lie on to the positive part of the imaginary axis. Write f as a composition of horizontal translations, scalings, and inversions.
2. Compute f(x) and f(y).
3. Compute d_{H^2}(f(x),f(y)) and verify that f is an isometry.
In: Advanced Math
Could Anybody explain about THE CONTRACTION MAPPING THEOREM with easy definition and few easy examples ?
I am having very hard time understanding it :((
In: Advanced Math
Consider the following nonlinear differential equation, which models the unforced, undamped motion of a "soft" spring that does not obey Hooke's Law. (Here x denotes the position of a block attached to the spring, and the primes denote derivatives with respect to time t.) Note: x3 means x cubed not
x''' x′′ - x + x^3 = 0
a. Transform the second-order d.e. above into an equivalent system of first-order d.e.’s.
b. Use MATLAB’s ode45 solver to generate a numerical solution of this system over the interval 0 ≤ t ≤ 6π for the following two sets of initial conditions.
i. x(0)=2,x′(0)=−3
ii. x(0) = 2, x′(0) = 0
c. Graph the two solutions on the same set of axes. Graph only x vs. t for each IVP; do not graph x′. Be sure to label the axes and the curves. Include a title that contains your name and describes the graph, something like “Numerical Solutions of x′′ +x− x3 = 0 by I. M. Smart.” (obviously your name!). Make sure to include a date/time stamp on the graph, Note: To get x′′ to appear in your title you will have to type x′′′′ in your MATLAB title command.
d. Based on your graph, which solution appears to have the longer period? Explain clearly how you arrived at your answer
In: Advanced Math
In: Advanced Math
In: Advanced Math
Provide a detailed report on below topics and submit all the files (Excel, word and SAP2000)
Design of Transmission towers using SAP2000
In: Advanced Math
L. Houts Plastics is a large manufacturer of injection-molded plastics in North Carolina. An investigation of the company's manufacturing facility in Charlotte yields the information presented in the table below. How would the plant classify these items according to an ABC classification system?
(Round dollar volume to the nearest whole number and percentage of dollar volume to two decimal places.)
Item Code Avg. Inventory (units) Value
($/unit) Dollar
Volume % of dollar
volume
1289 400
3.50
_____
______
2347 300
4.00
1,200
36.97
2349 120
2.50
300
9.24
2363 65
1.50
____
____
2394
60
1.75
105
3.23
2395 25
1.75
____
_____
6782
20
1.15
23
0.71
7844 12
2.05
25
0.76
8210 10
2.00
___
___
8310 7
2.00
14
0.43
9111
6
3.00
18
0.55
___________
3,246
What is the highest dollar volume percentage?
The concept of ABC category analysis is based on
A. statistical sampling, i.e., sampling a few items to get control of the whole inventory.
B.controlling the maximum number of inventory items with moderate effort.
C.controlling the maximum number of inventory items with minimal effort.
D.controlling the maximum amount of money with minimal effort.
In: Advanced Math
7.Find the number of{0, 1, 2}-strings of lengthn in which 0 appears an even number of times and 1 appears an odd number of times.
In: Advanced Math
A student is standing still at the front doors of Maple. They start running to catch the bus at
2
(a) How far away is the bus stop if they reach the bus stop after accelerating from standing still until reaching maximum speed and running at that speed for 1 minute? (assume when they reach the bus stop they are at rest.)
(b) Suppose that the student gets to the bus stop and realizes they forgot their laptop in Maple. The next bus arrives in 2 minutes. However, they are extremely tired at this point, and their max running speed is now 6 ft/s. Can they run back to maple and return to the bus stop in time? (Assume their acceleration remains the same)
(c) Alternatively, suppose the student is running from Maple Hall to Sieg Hall which is 2000 feet away. Find the time (in seconds) it takes the student to travel this distance. (Assume they are at rest when they reach Sieg.) Use 7ft/s & 2 ft/s^2.
In: Advanced Math
explain in your own words how to construct a perfect square trinomial, a difference of two squares and/or a polynomial with a common factor. In other words, if you were teaching a math class, how would you construct problems to practice one or more of those skills?
Choose one operation (addition, subtraction, multiplication or
division) and give an example of that operation on fractions and on
rational expressions (you may select an example from Chapter 6 of
the text or your MML problem set). Alternatively, you may choose to
work with equations containing fractions and equations containing
rational expressions. Explain how the procedures are the same
and/or different for the two examples.
You have learned several ways to solve quadratic equations –
factoring, the square root method, completing the square and the
quadratic formula. Pick one method and describe when it is and is
not appropriate to use that particular method. Include an example
of a problem that is easily solved using your chosen method and one
that would be easier solved using a different method.
In: Advanced Math