Stuck Definition and 836 Threads

Homework Statement Hello, I am stuck on this particular question for my homework. It is a 4x4 Matrix that consists of a b b b b a b b b b a b b b b b The Attempt at a Solution My approach has been to factor out the a to give the first row of 1 b b b and then use...

Homework Statement I've spent the last hour trying to get this, and it's starting to drive me crazy! I'm not sure how to approach the waveform, as there are two forms? I'm guessing that the period in this case is 4 seconds, and they've included a second wave to reiterate that? Homework...

I have been working on this problem for a while and I am stuck, Can I get some hints pls? Thanks.

Homework Statement I am required to make a projectile launcher of some form that will fire a golf ball a certain distance, a certain height through a window, and to have it land accurately on a target. -The device can only be 1x1x1 meter - no weight restrictions. -There will be two launches...

Homework Statement Hello! I am in the middle of the integration process. Can you give me suggestions on how to simplify the last equation? Thank you! Please see the attached snapshot of my work.

Homework Statement Solve the following equation in N^3: x^2+y^2+z^2=xyz-1 The Attempt at a Solution I moved all the terms to one side, but I don't know what to do from there on.

Dear all, I am a medical doctor stuck with a mathematics problem. I have taken a project to map the 3D movement of a particular bone and describe its motion. My maths knowledge is a bit lacking. However using logic I felt that I would need to track 3 constant markers on the particular bone...

if my car is stuck in a hole... I'm just doing a taught experiment, and i want to be able to prove or not that pushing down on a car that is stuck in a hole(increasing down force) uses less work force than pushing it from the back. edit: what i came up with is- ASSUME my car is 10kg and it...

Homework Statement ε[1]=12v internal resistance[1]=.016Ω ε[2]=12v internal resistance[2]=.012Ω some unknown resistance 'R' in a stand alone resistor. a) what value of 'R' will make the terminal-to-terminal potential difference of one of the batteries zero? b) which battery would it be...

Homework Statement Ʃ n/e^n converge or diverge Homework Equations The Attempt at a Solution I got this down to an improper integral using the integral test but I am weak at L'Hospitals rules and I was wondering if someone could help me out I have \int n/e^n from 1 to...

Homework Statement A company mines low-grade nickel ore. If the company mines x tons of ore, it can sell the ore for the price p = 225 - 0.25x dollers per ton. How much revenue will the company make by selling an additional 1 ton of ore on top of what is being produced to maximize revenue...

Homework Statement I have a function F defined in a slightly strange way, and I'm not asked to test if curl(F) == 0, but I thought I would do this as part of my working out. Lo and behold, it looks like it doesn't == 0, and this means, as far as I know, that there is no scalar potential but...

Homework Statement Find a power series for the function, centered at c, and determine the interval of convergence. Homework Equations g(x) = 2 / (1-x^2) , c=0 The Attempt at a Solution 2 / (1+x)(1-x) = 1/(1+x) + 1/(1-x) 1/(1-(-x)) => Sum [(-1)^n (x^n)], n=0 to infinity. Converges when...

I'm building a simple 20:1 gearbox prototype with 2 compound gears in a row connecting to a third small gear at the end. My goal is to multiply the rotational speed of the small gear. They are all engaged on a straight line. But for some reason they get stuck most of the time. I'm trying to...

1. A projectile motion is fired horizontally at 150ms-1 from the top of a 196m high cliff. Calculate its velocity on hitting the ground. 2. Okay so I've already discovered its time of flight t = 6.32s and its range Δx = 948m. Other figures are Δy= 196m, ay= -9.8ms-1, ux=150ms-1, Vy=...

Question: Dreamboat cars are produced at three different factories A, B, and C. Factory A produces 20% of the total output of Dreamboats, B 50%, and C 30%. However, 5% of the cars at A are lemons, 2% at B are lemons, 10% at C are lemons. If you buy a Dreamboat and it turns out to be a lemon...

q) A force F acts on a block of mass m placed on a horizontal smooth surface at an angle Θ with horizontal. Then (A) If F sinΘ < mg then a = (F + mg) / m (B) Acceleration = FcosΘ/m where, F > mg cosecΘ (C) Acceleration = F/m if FsinΘ > mg (D) If F SinΘ > mg then a = (F + mg) / m...

If an object is between 2 large masses with high gravity, that haven't come together (gravity of other large masses is keeping them apart) does the object between them get pulled violently apart or does the gravity balance out?

Homework Statement Find the general solution for the equation (x - 1)y'' - xy' + y = sin(x), x > 1 Given that y_1(x) = e^x satisfies the associated homogeneous equation. Homework Equations y_2 = v_2(x) * y_1 The Attempt at a Solution I read...

Hey ya'll! This is the equation under discussion: y'' - 2y' - 3y = x + 2 I'm asked to use the method of variation of parameters to determine a solution for this differential equation, but I reach a point where my the equations just look too ridiculous to continue. The point I have in...

I'm not sure where I'm going wrong on this one so I hoped that I could find some help we begin with (x^2 + y^2 + 5) dx - (y+xy) dy taking both partial derivitives I found that 2y (dy) =/ -y(dx) Next I went to find my factor of integration using e^(My - Nx / N) dx)This got me ((1+x)^-3)...

I've been working at a small R&D company for almost 8 years since my PhD. The things I do are not particularly related to my thesis research. I've had some projects of my own that went fine, but mostly I've ended up working on co-workers' stuff. Being a small place with a capricious...

Homework Statement What is the general solution of tv' + v = 0? book says it is v(t) = c/t but i don't see how i tried to solve like this: v' + (1/t)v = 0 p(t) = 1/t P(t) = Ln(t) y = e^ln(t) + c = t + e^c please help,thanks Homework Equations The Attempt at a...

Homework Statement Suppose the function f:R^2→R has 1st order partial derivatives and that δf(x,y)/δx = δf(x,y)/δy = 0 for all (x,y) in R^2. Prove that f is constant; there exists c such that f(x,y) = c for all (x,y) in R. There's a hint as well: First show that the restriction of...

Homework Statement 1.Hibernation is a state of regulated hypothermia, lasting several days or weeks, that allows animals to conserve energy during the winter, During hibernation animals slow their metabolism to a very low level, with body temperature and breathing rates lowered, gradually...

I am writing some code which involves numerical integration of a function on a 3D grid of points. I am defining the type vector to refer to these points, and I am also trying to extend the intrinsic operator * to include scalar and vector multiplication. However, I cannot compile and I don't...

Homework Statement A galvanic cell consisting of two silver electrodes,one in a saturated solution of AgBr and the other in a saturated solution of Ag2CrO4 is prepared.Calculate the value of Ecell at 298K Given Ksp(AgBr) = 5x10-13 M2 and Ksp(Ag2CrO4)=2.4x10-12M3 Homework Equations to...

Homework Statement Show that the exact value of tan°43' is \frac{\sqrt{5}-1}{2} Homework Equations The Attempt at a Solution tan2x = \frac{2tanx}{1-tan^{2}x} \frac{2tan31° 43}{1-tan^{2}31° 43'} From here, i got stuck or I'm doing it wrongly, i forgot how to do it...

Homework Statement I've worked through and been able to understand each problem I've been given except for the following two, does anyone have a suggestion or an explanation on how to solve either of these problems? Thanks in advance. 1. "On the first part of a 317 mile trip, a sales...

solving for commutator in QFT I am just starting to learn quantum field theory. I'm still an undergraduate but I love particle physics and I want to get ahead, so I got the book "introduction to quantum field theory by peskin and schroeder" I got to page 21 and I'm already stuck at an integral...

Homework Statement I know it needs L'Hopital but i can't get it to the indeterminant form Limit (x-(x+2)e^(1/x)) ((inf - inf )) x-->inf I reached until here and then i got stuck (1-((x+2)e^(1/x))/x)/(1/x) (1 -inf/inf)/0

Homework Statement ∫x^2/(x^2+4x+8)dx Homework Equations N/A The Attempt at a Solution I've tried a few things so far and nothing clicked, I may be just missing something obvious ... if anybody sees the solution and could just give me the first step or a hint, that would be sweet...

Hey all, I need some help rearranging for R. O=R{1-Cos(28.65S/R)} For those curious, its a Horizontal Sightline Offset formula used in geometric road design. thanks

I'm currently re-teaching my self maths to get into physics as i sucked at maths in school but now I am older I feel like actually learning it ! So I'm on a website which gave me a test quiz i got them all correct bar one but it won't tell me the answer so ill show you the question and my...

Homework Statement Homework Equations I am trying to do some self study here before I take my circuits course. I am stuck on this problem for some reason.. The equation I am coming up with for the node is : 6 - Vo/2 - Io/4 - Vo/8 = 0.. After getting at equation I can't seem to come to...

I am stuck with this problem,the dependent current source is creating a big problem for me, please help. I have attached the problem.

In the last 2 weeks we've begun learning about eigenvalues/vectors. It will come up in my exam in January so I'm trying hard to get my head around this. I've tried various different sources to learn this but I'm hoping someone here can offer a different view on it. Basically, I can work out the...

Hello Physicsforum, I am trying to compute the following double sum: \sum_{j\in\mathbb{N}_0/2}\sum_{m=-j}^j\frac{x^{j+m}}{(j+m)!(j-m)!}e^{-\kappa^2j(j+1)/s} where x, kappa and s are parameters. It is possible with e.g. Mathemtatica to carry out the sum over m explicitly, which yields...

Suppose you are building a sequence consisting of 0 and 1 in such a way that: - you start with 1 - no consecutive 0s are allowed Examples of such sequences are: 1, 1010, 110111101 etc. Empty sequence is also allowed. I want to prove by induction that the number of 0s in such a sequence is...

Homework Statement There's a cannon sitting at the edge at the top of a 350 m cliff that fires a 15kg projectile at a muzzle velocity of 250 m/s. On the opposite side there's another cliff that is 470 m in height from the bottom of the canyon as well and has a target on it. So the...

I am a junior in high school I am at a total lost to what college I should apply to and what I should major in. I know that I want to work on molecular assemblers later in life, but I don't know what school will be best for me. Can anyone please help me find out which school I should apply to...

Homework Statement Okay so here is the problem: A golf ball is struck and leaves the ground at 96 m/s on a 60 angle. Determine the velocity of the ball 2 seconds after it was struck. I have the answer provided, which is 32.6 m/s at 45° above the horizon. Homework Equations Obviously I...

Homework Statement Assuming that ∅ is a differentiable scalar valued function and F a differentiable vector field, derive the following identities. a)∇(dotted with)(∅F) = ∇∅(dotted with)F + ∅∇(dotted with)F b)∇(crossed with)(∅F) = ∇∅(crossed with)F + ∅∇(crossed with)F Homework Equations The...

I have the infinite series... \sum n^n/n! somehow, I need to use the Ratio Test... and shoe that the resulting limit is equal to e. I can't figure out what I am doing wrong algebraically. Right now I have simplified this limit to lim((n+1)^n/n^n). Please Help... Thanks.

because the molecule is extremely cheap and can't be patented? This is from Johns Hopkins University too, not some quack on the internet: http://www.sciencedirect.com/science/article/pii/S0006291X04020625 http://www.ncbi.nlm.nih.gov/pubmed/20420565 If you can get to a university library you...

I am completely stuck on where to go with the following ODE: (D^4 + 1)y = 0 where D=d/dx I know that trying y=e^(rt) is the obvious solution, however, when you solve this you get r^2 = +-i. At this point I am unsure of what to do becuase if I take the square root of "i" I am unsure of...

Homework Statement This is the question i am asked: Determine a suitable size for the (gantry girder) beam selected from standard section tables. Prior to that is some information: The cross-section of the beam shows that of a Gantry Girder. The maximum bending stress in the girder...

As of late, I'm at my computer nearly all day, watching F.R.I.E.N.D.S and reading stuff on PF. I've also started reading the latest arcs of the Batman comics. There's that and bits of studying thrown in. Actually, that's what I've been doing ever since we shifted from dial-up to broadband...

Homework Statement Hi, my question is lim_{x\rightarrow0}x2\frac{cos(cot(x))}{sinx} Homework Equations The Attempt at a Solution I thought maybe I could make \frac{cos(cot(x))}{sinx} similar to \frac{sinx}{x}, but couldn't find a proper way for it. Dividing sinx by cosx and...