Solve x(y^2+U)Ux -y(x^2+U)Uy =(x^2-y^2)U, U(x,-x)=1
In: Advanced Math
In: Advanced Math
3. The Krov band is touring the UK. They have played eight dates and already their tour is a great success. Total post-gig sales (merchandising, CDs etc.) on each date have been:
Date no. |
Sales (£000s) |
|||
1 |
3 |
|||
2 |
7 |
|||
3 |
15 |
|||
4 |
14 |
|||
5 |
18 |
|||
6 |
21 |
|||
7 |
16 |
|||
8 |
22 |
|||
9 |
||||
In: Advanced Math
data:
weight in lb | Mat-A | Mat-B |
49 | 13.2 | 14 |
51 | 8.2 | 8.8 |
46 | 10.9 | 11.2 |
50 | 14.3 | 14.2 |
51 | 10.7 | 11.8 |
47 | 6.6 | 6.4 |
44 | 9.5 | 9.8 |
47 | 10.8 | 11.3 |
46 | 8.8 | 9.3 |
In: Advanced Math
For each of the following data sets, write a system of equations to determine the coefficients of the natural cubic spline passing through the given points.
x| 2 4 7
-------------
y| 2 8 12
In: Advanced Math
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