Multiple Definition and 1000 Threads

Homework Statement Four 335 kg spherical masses are placed on the corners of a square at coordinates (0, 0), (0, 1.50), (1.50, 0) and (1.50, 1.50) where all coordinates are in meters. What is the net gravitational force on the mass at (0, 0) due to the other three masses? Express your answer...

Hi, I have a MATLAB function m file and I want to integrate the function. function y = myfun(t,a,b) y = (1/(2*pi)).*(1./t)*(1i*(a+b)); endThen when I call the integration in MATLAB I don't know how to specify a and b whilst integrating over t. I need to be able to set a and b outside of the...

I am not sure if I am doing this correctly, so please check my attempt: I have four discrete random variables: G, H, J, L Say, I want to find P(H|J, G, L). Then can I write as P(H|J, G, L) = P(J, G, L|H)*P(H) = P(J|G, L, H)*P(G|L, H)*P(L|H)*P(H) Are those equivalent? I can't find an...

Homework Statement The Problem goes as follows: Palladium forms three different compounds with sulfur. The mass of sulfur per gram of palladium in each compound is listed below: Compound Grams S per Gram Pd A 0.603 B 0.301 C 0.151 Show that these...

If I want to plot multiple iterations of a while loop on one plot, how can I do that? Every time I use "hold on", it just distorts the original line after every iteration instead of drawing independent lines. Please help

Consider the multiple regression model containing three independent variables y = B0 + B1x1 + B2x2 + B3x3 + u You are interested in estimating the sum of the parameters on x1 and x2; call this O1 = B1 + B2 a) Show that O hat1 = B hat 1 + B hat 2 is an unbiased estimator of O1. b)...

I am sooo lost in this class, please help. 1. Let the true (population) model be y = B0+B1x1+B2x2+u where u is an unobserved error term with u (conditional) x1, x2 and N(0, sigma^2). Hence, u is normally distributed with mean 0 and variance sigma^2 (i.e., E[u (conditional) x1, x2] = 0 and V...

I was wondering how they did come up with the way of setting permissions using the linux program chmod by just using numbers. For example: 1 is for execute 2 is for write 4 is for read Any sum of those give a unique permission to a file: 2+4=6 Let's you write and read it. 1+4=5 Let's you...

I am working in FORTRAN I need to avoid writing to the same file at the same time while working in a parallel environment. I have a program (that I have not written and cannot edit) that calls a subroutine (that I have written and can edit). The subroutine is called over and over again by...

Two students are taking a 10 question test. Each question has 4 different answers. How many ways can each student answer the test? What is the probability that these two students get the same answers? I know that to get the number of ways to answer, the number of students is irrelevant. nk...

Compare the mass ratios of N2O3 and N2O5 and prove the law of multiple proportions holds true. I'm having trouble understanding what the question is asking for. So far, I've done this: N2O3: N: 14g * 2 = 28g O: 16g * 3 = 48g N2O5: N: 14g * 2 = 28g O: 16g * 5 = 80g...

Hi everyone, I have trouble understanding the multiple delta function. For one dimensional delta function, we have δ(\varphi(x))=\sum_{i=1}^{N}δ(x−xi)|\varphi′(xi)| where xi's (for i = 1 to N) are simple zeros of f(x) and it is known that f(x) has no zeros of multiplicitiy > 1 but...

Homework Statement D = (L + E) / S Where L, E, and S are mutually independent random variables that are each normally distributed. I need to find (symbolically), the conditional PDF f(d|s). Homework Equations The Attempt at a Solution Not sure what to do with so many...

Dear Fellows, I need to plot a graph in matlab, and stuck in obtaining multi plot from it for different constant values... following example will explain my situation. x=1; y=3; c=x^2+4y+9z z=linspace(0,1.2); plot(z,c,'r') in this I want to plot for y=3,y=4,y=5 and y=0 all curves in...

Hi all... my first time here... I hope someone can help. I'm toying with a home project (in the early conceptual stage), and the attached picture shows "in general terms" what I'm trying to figure out. The outer 'wheel' rotates about its central axis, driven at that axis by a small motor...

Homework Statement lim as x approached 2 from above of: (x1/2 - 21/2 + (x - 2)1/2)/(x2 - 4)1/2 Homework Equations L'Hopitals rule... The Attempt at a Solution I tried susbtituting in 2 and found that I got 0/0 thus it was possible to use L'hopitals. I then got inf/inf, so I used it again...

[ANSWERED] Mathematica -> making multiple variables in one go? Ok so let's say i know how many variables i want: numberofvariables = 5; and then i want to create 5 different variables, say X1, X2, X3, X4, X5 based on some formula, say: Xi = 5+i^2 but i want this creation of...

Hello all, I understand that the taylor expansion for a multidimensional function can be written as f(\overline{X} + \overline{P}) = f(\overline{X}) + \nabla f(\overline{X}+t\overline{P})(\overline{P}) where t is on (0,1). Although I haven't seen that form before, it makes sense...

Homework Statement Homework Equations The Attempt at a Solution But the correct answer is 1227 ft/s^2. Thanks.

Homework Statement I am asked to solve for vX, PDEV BY iS1, P ABS BY vS3 (please see attached figure). We have only covered KCL, KVL, Ohm's law and Power in class. No Thevinen theorem, so it can't be used to help solve. The Attempt at a Solution I know that current will...

Hello guys I wonder if you can help me? Basically for a project I’m going to produce a led light source with 12 leds with a single small driver that runs on 24v supply. The LEDs run 3.7v typically so that would require 44.4v that’s a lot more than the led driver can supply but if I run 2x 6...

Hello, why when I connect 2 or more battery in series the voltage at the extremes of batterys will be the sum of single batteries voltages? what happen phisically? how the electrons of second battery go to the positive pole if they must pass from the first battery? Thanks!

hi I have multiple torques acting at different points on a rigid body I want to find the resultant force and torque (about the body CM) I think I can see how to "convert" an off-center torque to a torque + translation using the parallel axis theorem - but am wondering if there is a...

Hi all, I wondered if you guys could help me with this question. I have been showed a picture of a lightning. It is not the complete lightning on that picture, maybe 1-2 thirds of it. To me it looked a little blurry, so I asked if the photographer had used a tripod to make sure the camera...

Hi! Yesterday i read and mostly understood that (cos(\theta) + isin(\theta)^{n} = (cos(n\theta) + isin(n\theta)

Homework Statement After a period of time the frame contains four crates. Calculate the distance of the centre of gravity from the support A.Homework Equations The weight is 200KG per crateThe Attempt at a Solution I know how to calculate the centre of gravity but this problem is stupid...

I found a list of all the possible valences of all elements online, but say were dealign with a compound with iron, has multiple valences, how do i know which valence to use when? this has been bugging me for quite some time, any ideas?

Hi everyone, haven't been posting here for a while now...And as always, I come with a doubt xD I want to activate a simple circuit (one that swtiches a transistor ON and OFF) via RF (any other wireless communication method is very well welcomed, except optical of course). The thing is, I...

The problem is: R is the parallelogram bounded by the lines x+y=2, x+y=4, 2x-y=1, and 2x-y=4. Use the transformation u=x+y and v=2x-y to find the area of R. I am not sure how to complete this problem. My first issue is that I don't know how to convert the transformation functions into...

Assume you have a brand new Diesel or gas pickup truck of any brand and factory specs you choose. Assume there is a dolly connected to that pickup truck. How many of the same pickup/hitch/dolly combination trucks could the first truck pull if you have them lined up like a train (and the trailing...

Hi The following structure has 2 elements. people = struct(... 'name',{'bob', 'john'},... 'numKids',{0, 2}, ... 'kidsage',{[],[12,9]}); each element people(1), people(2) has three frields (name, numKids, kidsage) Instead of declaring the structure in one line as above...

Suppose I have the PDE: \frac{\partial^{2}u}{\partial x^{2}}+\frac{\partial^{2}u}{\partial y^{2}}=\frac{1}{c^{2}} \frac{\partial^{2}u}{\partial t^{2}} with u(0,x,y)=\partial_{t}u(0,x,y)=0 along with u(t,0,y)=f(y) With x\geqslant 0. My initial thoughts were to take the Laplace transform in t...

I'm trying to determine the contact surface area of a threaded bolt so that I can make some changes to the design and maintain the same contact surface so as not to affect the performace in other ways. This presents itself as a helix, and my initial guess was that it may be best to work this...

This is my SQL in PHP SELECT * FROM ExamQuestions where exam_id not in(Select ans_exam_id from StudAns where ans_user_id=".$_COOKIE['cuserid']." and ans_exam_id in(SELECT exam_id FROM ExamQuestions)) ORDER BY RAND() when multiple users send this query to server it slows down. is there any...

If KE=(m V^2)/2 Then V=matrix([[(2^(1/2)*KE^(1/2))/m^(1/2)], [-(2^(1/2)*KE^(1/2))/m^(1/2)]]) Would this notation be considered improper? I'm just wondering because this is what my computer printed out. or something like this V=matrix([-5],[5]) m/s Is this acceptable?

I've got a few diagrams (on the twin paradox), that I'd like to repost occasionally. It seems that if I just post a link, people are less likely to look at them. PF, however, complains that I've already uploaded the file. I can tweak it a bit, and re-upload it, but that seems anti-social...

Hello everyone. In Mathematica® I want to numerically integrate a function of k variables (k varies) with respect to all of them. Does anyone of you know a way to do that? I tried the following simplified example. k = 5; int[x_] := x[[1]] + x[[2]] + x[[3]] + x[[4]] + x[[5]] ; (* My...

Lets say...a little bit after the double slits, we place another set of double slits (one pair of double slits for each of the "original" double slit) thus a total of 6 slits two slits in the first plane (say at y = 10) and four in the next plane/series (say at y = 10.02) the x-axis (and...

For instance lead has 2 valences it says here +2 and +4 is there some place i can find a refference of all multiple valence elements(they tend to be transition metals) i found one on wikipedia. but it only gives one of the valences, not both or several.

An interesting electrostatics puzzle! This is a simplification of a real problem I've been hurting my brain on. Luckily the simplification is a fun challenge in its own right. Homework Statement There is a 3D rectangular solid object in space. Each face of the solid is a perfect...

I was thinking about the time reversal explanation of the double slit experiment, where the anti-wave-particle goes back in time and interferes with the wave-particle that we observed hit the target. Since we don't actually observe this phantom particle that is traveling back in time (and...

Homework Statement Two lenses, with 20cm focals are in 1m distance from each other. A body is located 60cm from the right lens.Homework Equations I figured that the relevant equation should be: \frac{n1}{u} + \frac{n2}{v} = \frac{n2 - n1}{r} but perhaps a I'm wrong. The Attempt at a Solution...

Statistics, multiple choice, regression equation -- 2nd question Homework Statement A regression equation was developed to predict gasoline mileage (mpg) for various car weights (pounds). The resultant equation was: Y = 35.2 - .0034 X. Which two answers can be concluded? A. The...

Homework Statement The correlation coefficient for each of two data sets is calculated. Set A has r = -0.75 while Set B has r = +0.55. Which set (A or B) has the stronger strength of relationship? Homework Equations I think -0.75? The Attempt at a Solution I think Set A r =...

Hi friends, I need to get the surface equation like function f(x,y) that passes through 66 points. I attached the file xls where is the points, and a pdf file where is the graphics of the points. Can somebody help say me that I have to do for solve it?

I’ve been searching high and low for an answer to this question. What actually HAPPENS if two engines were to power one drive shaft? I heard back in the days that cars were built this way to break speed records, and I heard present day it is used in tractors, but what increase. My question...

Homework Statement How many images of a symmetrically placed object will be formed if 2 plane mirrors are fitted on ADJACENT walls of a room and another one on the top(roof)? (mirrors are big) 2. The attempt at a solution According to me,9. because,3 direct images of the object are...

Cauchy Integral Formula -- Multiple Possible Solutions? I'm in the process of teaching myself some complex analysis, and I ran into the following conundrum: Homework Statement Suppose one was given an integral, \int_C \frac{1}{(z-a)(z-b)} \mathrm{d}z where C is a closed curve with a and...

I have a dat file with multiple data sets, with the following structure: # t = 0.0 , ... -10.000 0.00001 1.000001 ... -9.000 0.00002 0.900001 ... ... 10.000 0.00005 1.000001 ... # t = 0.2 , ... -10.000 0.00301 1.000203 ... -9.000 0.02222 0.900043 ... ... 10.000 0.00025 1.000551...

Homework Statement suppose you put 5 electrons into an infinite square well. (a) how do the electrons arrange themselves to achieve the lowest total energy? (explain with help of diagram) (b) give an expression for this energy in terms of electron mass, well width L and planks constant The...