Terms Definition and 1000 Threads

Homework Statement Let Sn = 1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}...+\frac{1}{n}. Show that |S2n-Sn|\geq \frac{1}{2} Homework Equations The Attempt at a Solution So I'm going to try and use induction Base case let n=1 |S2n-Sn| = \frac{1}{2} So true for base case...

I've been working on problems that deal with pendulums and I've noticed that a few of my answers require me to find the angular velocity, frequency, period of a pendulum. I managed to get the answer right every time, but there's a step that I didn't understand, namely converting angular...

Homework Statement I am attempting to manipulate this equation into a form that, presumably, has 3 Sinc terms. I am attempting to do this because my professor has written "reduce the solution to terms having sinc functions", and I am assuming there are 3, because plotting this equation in...

I'm trying to keep a balance in difficulty next quarter and would appreciate some feedback as to the difficulty of these classes. The four I'm choosing between are Linear Algebra (upper division), Linear and Nonlinear Systems of Differential Equations, Ordinary Differential Equations, and...

Hello guys. I would like someone to check that I am doing this problem correctly. The answer given in the book is 0.577(P) for FAB and FAE which differs from the answer I get. Homework Statement Determine the force in each member of the truss in terms of the load P and state if the members...

Homework Statement "A satellite orbits the Earth in a circular orbit of radius r. If the orbital speed of the satellite is v, what is the orbital period T of the satellite in terms of v and r? You must explain how you derive the expression for the period."Homework Equations Speed =...

Please do your best to describe E=Mc^2 to me in the most plain English you know and as basic as possible without leaving out details. Any links you think would help would be great. Thank you

I graduated from high school this year and took the three main sciences (biology, chemistry and physics) as well as math up to Calculus. I've decided to take a year away from school for a couple reasons. But that doesn't mean that I must stop learning. Recently I bought a book which gives...

Homework Statement The adiabatic bulk modulus is defined as: \beta_s=-V(\frac{∂P}{∂V})_sExpress it in terms of experimental variables: C_p, C_v, \alpha, \beta Homework Equations Heat capacity at constant pressure:C_P=(\frac{∂Q}{∂T})_P Heat capacity at constant volume:C_V=(\frac{∂Q}{∂T})_V...

I was just reading an article on superstringtheory.com in the Black Holes section entitled "Space, Time, and String Theory" when I came across the following predicted reformulation of Einstein's tensor: The explanation for this was as follows: My question is this: are those correction...

Homework Statement Find Vo as a function of Vg and the open-loop gain A. Attempt I'm not sure what open-loop gain means. I redrew the circuit so it made more sense to me, but I'm still not getting it. It seems that Vo is the voltage across both RL and the 4k resistor. The...

Hello, I need your help in clarifying some points from Normal Distribution Theorem: What does this expression exactly says: P(Z<=z) ? Z is random variable? z is deviation?

I realized that one of my main problem is remembering terms like, whole numbers, rational numbers, etc. I was just wondering how important was it that I actually know these terms? I can do the math, just have problems with some of the terms.

Homework Statement Write down formulae for dX in terms of dA, dB, dC if: X = [(A) (B^2)] / C Homework Equations I'm using the formula below as this corresponds to this relationship. (dX/X)^2 = (dA/A)^2 + (dB/B)^2 The Attempt at a Solution For the first line, not the...

Homework Statement My book talks about the "reduction formulas" for evaluating trigonometric integrals by parts. However, is this the same thing as "recursive" formulas for integration by parts, a term which is not mentioned in my calculus book? Homework Equations The Attempt at...

Homework Statement I was given this problem as homework and managed to find the solution online, but I don't fully understand it. My only question, and the reason I was getting this problem wrong, is because I wasn't realizing that the functions evaluated from -∞ to +∞ were vanishing...

Homework Statement Is mass a conserved quantity under Special Realitivity? Homework Equations E=mc^2 The Attempt at a Solution Total energy is always conserved in an isolated closed system, and since mass is just another form of energy, then mass would be conserved in a...

Problem statement: Define isOdd function, and then define isEven function in terms of isOdd function. My attempt is ridiculous: var isOdd = function (x){ if (x % 2 ===0){ return isOdd; }else{ return "is even"; } }; var isEven = function (){ return; };

I have been tasked with solving the following inequality: \frac{1}{x} < 4 Attached to this thread is my attempted solution. As you can see I begin with simply solving the inequality for x, and I obtain the result x > \frac{1}{4} Next, I convert the equation into what I thought was the...

What exactly do the terms "near-field" and "far-field" mean? What exactly do the terms "near-field" and "far-field" mean (especially in the context of the two problems attached)? Other than the confusion about those terminologies, I fully get how to do these problems (1.1 and 1.2). Any...

Homework Statement Suppose P is invertible and A = PBP^-1. Solve for B in terms of A. Homework Equations (AB)^-1 = B^-1*A^-1 The Attempt at a Solution multiply from the left of each side of the equation by P^-1: P^-1 *A = BP^-1 Take the inverse of both sides: (P^-1*A)^-1 =...

Me and a friend was contemplating the ratio of even to odd number in Pascals triangle. After some thought we arrived at a ratio like this when looking at a triangle of 2k-1 rows. \frac{2^{2k-3}+2^{k-2}}{3^{k-1}} - 1 As expected, this ratio grows exponentially. (I.e. almost all numbers in...

In the paper http://arxiv.org/pdf/hep-th/9301028.pdf pages 8-9 Pullin shows how to write the Einstein action in terms of tetrads e^a_I. Part of the proof is: "...the last term yields e_M^{[a} e_N^{b]} \delta^M_{[I} \delta^K_{J]} C_{bK}^{\;\;\; N}. It is easy to check that the prefactor in this...

Homework Statement I'm trying to express spherical coordinates in terms of cylindrical and vice versa. I would appreciate it if someone could give me some feedback on my attempt at a solution. Thanks for the help! The Attempt at a Solution Spherical(cylindrical) r=(ρ^2+z^2)^(1/2)...

hello! I think it would help a lot to visualize mathematical terms I would like to see the graphs of various f(x), then their f'(x), their f''(x), in order to understand what derivatives mean example: http://en.wikipedia.org/wiki/File:Graph_of_sliding_derivative_line.gif same with...

I just started grad school from an engineering background. My research has led me to need more physics & math which is why I'm in the class, but I don't have a very broad Math background. This problem given is exactly as it is typed above. The text we are using is Arfken: Math Methods for...

I'm trying to work out equation 2.45 in these notes: http://www.damtp.cam.ac.uk/user/tong/qft/two.pdf Anyway \phi(\vec{x}) and \pi(\vec{x}) are given in equations 2.18 and 2.19 When I multiply out \pi(\vec{x}) \vec{\div} \phi(\vec{x}) I get four terms. After normal ordering I can combine two...

Dear PF users What is the rationale for Sze to write the exponential terms in ch. 1, Eq. 38 once as \exp \left[ -\frac{E_C - E_F}{kT} \right] and once as \exp \left[ \frac{E_F - E_D}{kT} \right] ? In both cases E_F is larger than either E_C or E_D. To me, for the sake of not having to worry...

Homework Statement "Show that if the Hamiltonian depends on time and [H(t_1),H(t_2)]=0, the time development operator is given by U(t)=\mathrm{exp}\left[-\frac{i}{\hbar}\int_0^t H(t')dt'\right]." Homework Equations i\hbar\frac{d}{dt}U=HU U(dt)=I-\frac{i}{\hbar}H(t)dt The Attempt at a...

'Ello, I have a question regarding the results in this paper (and another which I will mention later) http://arxiv.org/abs/hep-ph/0212199 Now, I'm not so concerned about the 'braney' bit, but more their definition of the cross section in Eqn. (46). They have included the usual (2j+1)...

solve the following equation for z in terms of x and y 3y^{2}+2yz-5z-2x=0 i've spent a lot of time on this question, but i keep getting something along the lines of 0=0 i tried solving for x in temrs of y and z to replace the x but i get 0=0 Homework Statement Homework Equations The Attempt at...

Hi all, I have a summation series which goes like this, S = [log(1)]^2 + [log(2)]^2 + [log(3)]^2 + ... + [log(n)]^2 Since each term is square of the logarithm of a value, I think there are no general tricks which can be used to solve this. But is there any way to approximate the...

Hey, I have the DE y'' -2y' + 3y = xsin(x) + 2cosh(2x) Using the D operator as D = \frac{dy}{dx} this becomes (D2 -2D +3)y = xsin(x) + 2cosh(2x) so yp = \frac{1}{p(D^2)} operating on xsin(x) + 2cosh(2x) (i think) So i know if this was say \frac{1}{p(D^2)} operating on...

Homework Statement 3. A particle with magnetic dipole moment of magnitude μ (be careful—this is not a magnetic permeability) and spin angular momentum of magnitude S is immersed in a magnetic field of magnitude B. For simplicity, assume that the spin and magnetic-moment vectors (which are...

Hello Given that english is not my native languagr, can you explain me please these terms and their differences: - function - equation - formula Thanks!

1. (x=X1+vt1, x1=x-vt ) 2.(t=t1+vx1/c2, t1=t-vx/c2 ) I know that 1. is x in terms x1 and x1 in terms of x. I understand it very well, the adding and substracting of velocity. But i am unable to understand the 2.how these equation are derived and what does they mean. The mane...

find no. of terms... Homework Statement find n 212,179,146,113,...... [b]3. The Attempt at a Solution here a=212 d=-33 but nth term or the sum is not given.any help will be appreciated thanks

I noticed that a lot of people simply use flashcards over and over again for studying the terminology of various subjects. Or they just re-read the terms and their definitions over and over again from their notes or textbook. While this can help you study for an exam via cramming, the problem is...

I have been reading this article and google-ing and still nothing, so here it goes What is: -P-type icosahedral? -Tsai-type quasicrystal? -1/1 cubic approximant? -six-dimensional lattice parameter a6D? -why has (this is example) powder X-ray diffraction spectrum just 2 high...

I am 99.5% sure I've got it right, but I keep second-guessing myself. 1] Cube with sides of length X. 2] Diagonals out from each corner of length no less than X... 3] ...to an outer cube of sides of length Y. What must be the (shortest) length of Y in terms of X? I get y = 2\sqrt{2}x

Hi All, Is it possible to express the kurtosis \kappa, or the 4th central moment \mu_4, of a random variable X in terms of its mean \mu = E(X) and variance \sigma^2 = Var(X) only, without having to particularize to any distribution? I mean, an expression like \kappa = f(\mu, \sigma^2) or \mu_4...

I don't know if this is the right forum or not, also, is there a specific forum on ftl travel? But can someone explain Heim theory to a high school student? I know the basics, and how it uses extreme gravitational forces to make the object/ship go to another dimension, where the speed of light...

The use of the terms "speed" & "velocity" This is a interesting topic concerning when to use these two terms in a discussion. Of course, if it is a vector term, then velocity must be used - however even for a scalar term, velocity could still be used. It seems to me that aside from the term...

True or False Questions. I have put my answers to them but one or more is incorrect, can anybody tell me which ones? Note: The linear system Ax=b of m equations in n unknowns is called: square if m=n overdertermined if m>n undeterdetermined if m<n homogeneous if b= 0 inhomogeneous b...

in this picture, there is a legend with the terms LINE and SINE in it http://i.imgur.com/IGJfm.png what do the terms LINE and SINE mean? I mean what do they stand for and what is their purpose in DNA. I have tried to look them up but it keeps going to math.

How would I solve this for x? I've been trying for a while now, and i can't seem to get anywhere. I just need some kind of hint. y=2x-\frac{3}{(2x-4)^2}

Hi, I am currently an undergraduate student of electronics and communication engg. in India. I have been extremely interested in physics since high school. I was planning to go for graduate school in physics. But I read a lot about the job prospects with a physics Ph.D. and considering...

Homework Statement Write the first 5 terms of the geometric sequence 3, __ , 32x+1, __, __ Homework Equations tn=arn-1 The Attempt at a Solution tn=arn-1 32x+1=3r3-1 r2=32x+1 / 3 r=√32x+1 / √3 I'm stuck

33 x 42 __________________________ = 2 x 3-3 x 16 33-(-3) = 6 16 = 42 ... 42-2 = 0 so.. 36 x 2 <-- answer I guess I am not sure

Hi I know that for an airfoil, it's typical to describe stall in terms of angle of attack. I'm wondering, how does Re play a role in flow separation of an airfoil (and for objects in general such as a plate, sphere, or cylinder)? One Wikipedia (http://en.wikipedia.org/wiki/Flow_separation) it...