Terms Definition and 1000 Threads

  1. S

    Linear Algebra: Solve B^(-1) with A, C, D

    I'm looking for help to this problem. Here is my attempt: I being the identity matrix and B^(-1) being B to the negative 1st power. A (B B^(-1)) C D = B^(-1) I so A I C D = B^(-1) so A C D = B^(-1) Thank you for any help.
  2. F

    Solving Implicit Equations for y in Terms of x

    How do you go about solving implicit equations for y in terms of x that look like these? y2 + yx = 1 and y3 + yx = 1 or even more complicated implicit equations. I'm taking AP Calculus AB this year and am just curious how this is done. Here are the solutions from Wolframalpha...
  3. E

    How Can We Validate Equating Terms in Infinite Summations?

    Today my physics professor briefly skipped over this during a derivation: We started with 2 \sum F_{n}(x) = \sum G_{n}(x) , summed from n=0 to \infty which she then concluded 2F_{n}(x) = G_{n}(x) where F and G are functions of x, and different functions for different values of n...
  4. W

    Recursive sequence terms don't cancel

    Homework Statement The following series is a telescopic series. Find the exact sum of the series by performing a partial fraction decomposition and generalizing the formula for the nth partial sum Sn. Homework Equations The Attempt at a Solution 3n + 2 = A(n+1)(n+2) + B(n)(n+2) + C(n)(n+1)...
  5. G

    Energy of an damped/undriven oscillator in terms of time?

    Homework Statement The Q asks to show that the time rate of change in mechanical energy for a damped, undriven oscillator is dE/dt=-bV^2.Homework Equations I assume you take the derivative of the total E eq, E=(1/2)mV^2 + (1/2)kx^2 but I'm unsure how to put the E eq into terms of t, like...
  6. T

    Mathematica Mathematica: Splitting a function into a list of terms

    Hi, I need to split an expression into a list of terms, i.e. an expression like: a+b-c-d+... into: {a,b,-c,-d,...}. Can you help? Thanks in advance.
  7. T

    Zeroth law of thermodynamics in terms of heat

    Is there any definition of the zeroth law of termodynamics using the heat concept? And does the zeroth law imply that the only way 2 systems can transfer energy is if they're not in thermal equilibrium? If 1 system is transferring energy to another one, that means they're not in thermal...
  8. L

    Splitting up exponential terms when integrating

    1. Relevant problem integrate from 0 to infinity of r^2exp^(-r/a0)dr Homework Equations I'm also given; integral from 0 to infinity of x^nexp^-x dx = n! The Attempt at a Solution I'm just wondering if I can split up the exponential to make it look like this form. Eg; integrate from 0 to...
  9. DryRun

    N(A) and R(A) in terms of their basis

    Homework Statement The matrix A = 1 1 1 1 -1 0 1 0 1 2 3 2 Express null space and row space of A in terms of their basis vectors. 2. The attempt at a solution I have found the null space to be: x3 [1 -2 1 0]^T + x4 [0 -1 0 1]^T. But my problem is how do i write the final answer correctly...
  10. M

    Higher order terms of Range Kutta for SPH?

    I am using smooth-particle hydrodymamics(SPH) method to model a deformable object. It is based on the procedure found in Markus Gross's point based animation book, the algorithm is attached in the image below. This algorithm uses Euler for numerical integration as seen in step 21 and 22, and...
  11. I

    Can someone explain polarization states to me in really simple terms?

    Let's say I have an equation E=iE0cos(kz-wt)-jE0cos(kz-wt), how do I look at this and know, this is linearly polarized? or what if it changes and the kz is negative? or its a sin function with with (wt-kz-pi/4) in it. I just don't understand what this equation is supposed to be telling me and...
  12. A

    Planning the year in terms of Research

    So I'm a second year Physics and Math major with the long term goal of a PhD in Theoretical Physics or maybe Math. I asked around at the start of this semester whether there was anything available for me in terms of research in the Physics department. I found a professor willing to take me on...
  13. M

    Starting initial value problems when terms are expressed only in x

    How should I go about starting the following two problems solve the following initial value problems x''-4x=0 ; x(0)=1, x'(0)=0 and x''-4x'+4x=0 ; x(0)=1, x'(0)=0 Should i use a general solution with the basis m^2-4=0 for problem one and m^2-4x+4=0 for the second?
  14. L

    Integrating double exponential terms in a function

    Hi, this is not really a homework problem, but something that came up during my research, upon trying to integrate some empirical function. This function consists of many terms, but specifically, there is a term containing double exponential functions which is giving me some trouble. If...
  15. R

    Classical mechanics - finding distance D in terms of velocity

    Homework Statement "A passenger (mass m) initially at rest steps out of an airplane. Assume down is the positive x-axis and put the origin at the airplane. Assume the air resistance force is linear in the velocity so F(air)= -mbv. Find the distance D he has fallen when his velocity is...
  16. V

    Evaluting Summation of Mutiplied Terms

    Homework Statement Evaluate the sums: \sum^{n}_{i=1}ia^{i} Homework Equations The Attempt at a Solution I'm assuming that because there's no limit or anything, the professor wants an equation. I know \sum^{n}_{i=1}i is \frac{1}{2}n(n+1) and \sum^{n}_{i=1}a^{i} is \frac{a^{n+1} - 1}{a-1}-1...
  17. W

    Second Derivative in Terms of Y

    Homework Statement Find the second derivative of 4x^2 + 3x - 9y^2. Answer in terms of y. Homework Equations All derivative formulas. The Attempt at a Solution [PLAIN]http://http://i52.tinypic.com/2w2ptex.jpg I can't get much further than this; the thing that gets me is how to put...
  18. N

    I would like to know more about the beginning of time in terms of

    I would like to know more about the beginning of time in terms of entropy. How can we explain the formation of a more ordered universe from a more ordered condensed structure that exploded and evolved to what the universe is right now? Where did the gravity come from and what is it's effect in...
  19. D

    Show that: Translator operator can be expressed in terms of

    Homework Statement The translation operator T(a) is defined to be such that: T(a)ψ(x) = ψ(x+a) Show that: T(a) can be expressed in terms of the operator p = -iħ d/dx and T(a) is unitary. Homework Equations T(a)ψ(x) = ψ(x+a) p = -iħ d/dx The Attempt at a Solution I honestly...
  20. jfy4

    Express electrostatic energy in terms of both charges

    Homework Statement For two concentric conducting spheres (radius a and b, b>a) that form a capacitor with charge q on the inner sphere and -q on the outer sphere, express the electrostatic energy in terms of q and -q and the potential difference between them.Homework Equations Gauss's Law, the...
  21. R

    Was the second originally defined in terms of the size of the Earth and c?

    I posted this first in Astronomy but it belongs in General Physics. With a little research, anyone can convince himself or herself that the following statements are true: a) that in one second light travels a distance equal to 30.0 times the distance between the north pole and the equator and...
  22. M

    Finding Inverse Hyperbolic secant in terms of logarithms ?

    The Problem is when I Compute the Inverse I have to solutions sech^{-1}(x) = ln(\frac{1\pm \sqrt{1-x^{2}}}{x}) : 0<x\leq 1 And this not function which of them I will choose Another Question is how can I prove without the graph that csch (x) is one - to -one thanks
  23. C

    Convergent series with non-negative terms, a counter-example with negative terms

    Homework Statement The terms of convergent series \sum_{n=1}^\inftya_n are non-negative. Let m_n = max{a_n, a_{n+1}}, n = 1,2,... Prove that \sum_{n=1}^\inftym_n converges. Show with a counter-example that the claim above doesn't necessarily hold if the assumption a_n\geq0 for all...
  24. P

    Rearranging terms in Trig equation

    I was reading on planetary motion and have gotten hung up on a "rearrangement of terms" that the author skimmed over. It reads that: r=e(k+rcos(θ))=(ek)/(1-ecos(θ)) It's been a while since I've been in a math class: I just can't follow how to get from a to b. Is there anyone who can walk...
  25. G

    Terms in a Mathematical Expression

    When we refer to terms in an equation, what EXACTLY are we referring to? Suppose for example we have: ab + bc + cd = A Suppose somebody refers to term "ab". Are they referring to the syntactical NAME "ab", the IMAGE of ab (i.e., it's value), or the ARGUMENT (a,b) which belongs to some...
  26. S

    Can anybody explain the modulation of radio waves in terms of photons?

    Hi All, I wonder if the modulation of RF waves (Amplitude Modulation, Frequency Modulation, and Phase Modulation) can be explained in terms of photons. Thanks, Srini
  27. L

    Questions on Chapter 67: Understanding the Limit and Contact Terms

    Hi, Just have a few questions about this chapter if anyone here is familiar with it... 1) Does anyone know why the k^2_i \to -m^2 limit is imposed in (67.4), is it just because he wants external particles to be physical and hence on-shell? I derived this equation from the one directly above...
  28. W

    Simple-Connectedness in Complex Plane: Def. in Terms of Riemann Sphere.

    Hello, There is a definition of simple-connectedness for a region R of the complex plane C that states that a region R is simply-connected in C if the complement of the region in the Riemann Sphere is connected. I don't know if I'm missing something; I guess we are actually consider...
  29. L

    Sequences of Functions in terms of x

    Homework Statement Determine the values of x for which the function, for n>=1, is increasing, decreasing, bounded below or bounded above. The function is (x^n)/n Homework Equations The Attempt at a Solution I thought about taking the derivative of the function, and setting it to 0. To find...
  30. R

    Why test charge slows down in terms of electric potential and EPE.

    Homework Statement a large positive charge +Q fixed at some location in otherwise empty space, far from all other charges. A positive test charge of smaller magnitude +q is launched directly towards the fixed charge. Of course, as the test charge gets closer, the repulsive force exerted on...
  31. S

    Explain phase change of an EMW in terms of photons.

    Hi Guys, I have a question. Can we attempt to explain the phase change of a carrier wave in terms of photons? For example consider GPS signal. It is BPSK modulated, in which phase change of 180 degrees happens for multiple of 1540 cycles of the carrier. How is the phase information...
  32. C

    How do the d terms in differential equations work?

    How do the "d" terms in differential equations work? Hi, I was hoping someone could explain how the "d" terms in differential equations work? For example, d2y/dx2 = 4x3 +1 To solve I have been rearranging to get, d2y = (4x3 +1)dx2 and then doing a double integral of each side...
  33. H

    Meaning of derivative in terms of interest rate?

    Homework Statement The total cost of repaying a student loan at an interest rate of r% per year is C=f(r). a. What is the meaning of the derivative f '(r)? b. What does the statement f '(10)=1200 mean? Homework Equations The Attempt at a Solution For part a I think the...
  34. C

    Multi-Variable Second Order Taylor Series Expansion: Ignoring Terms

    So I'm computing a second order Taylor series expansion on a function that has multiple variables. So far I have this I(x,y,t)=dI/dx(change in x)+dI/dy(change in y)+dI/dt(change in t)+2nd order terms Would it still be a better approximation than just he first order if I included some...
  35. J

    Expressing a decimal number in radians in terms of pi in a fraction

    Homework Statement arctan(sin((3 / 4) * pi) * 2) = 0.955316618 I want to express that in terms of a fraction with reference to pi. The Attempt at a Solution I thought of first dividing that by pi itself, and then convert the resulting number into a fraction and tack pi on at the...
  36. H

    Dimensions of temperature and charge in terms of M, L and T

    "Most physicists do not recognize temperature, Θ, as a fundamental dimension of physical quantity since it essentially expresses the energy per particle per degree of freedom, which can be expressed in terms of energy (or mass, length, and time). Still others do not recognize electric charge, Q...
  37. T

    Can I use Separation of Variables like this? (3 terms)

    \frac{\partial z}{\partial t}=\frac{\partial z}{\partial x}+\frac{\partial z}{\partial y} \mbox{Let }z=T(t)X(x)Y(y) T'(t)X(x)Y(y)=T(t)X'(x)Y(y)+T(t)X(x)Y'(y) \Rightarrow \frac{T'(t)}{T(t)}=\frac{X'(x)}{X(x)}+\frac{Y'(y)}{Y(y)} \Rightarrow \frac{T'(t)}{T(t)}=A \wedge...
  38. S

    What Are Control and Signal Regions in Particle Physics Experiments?

    I am recently reading the articles "Search for squarks and gluinos using final states with jets and missing transverse momentum with the ATLAS detector in sqrt s=7 TeV proton-proton collisions". However, as my limited knowledge, many technical terms that I am understanding as a result I am now...
  39. jaketodd

    Trying to get this PDE in terms of 'y'

    I will love forever whoever can show me the steps of how to get the following equation in terms of y=[...] This is not a homework question. I have a calculus book that has given me some progress, such as expanding the equation to a mixture of terms and first order partial derivatives, and I...
  40. T

    What is the pressure in terms of pi?

    Homework Statement The volume of a fixed mass of an ideal gas is doubled while the temperature is increased from 100 K to 400 K. What is the final pressure in terms of its initial pressure pi? Homework Equations in terms of pi? what?? does that stand for ' pressure initial or...
  41. S

    Explaining DCQE - via coherence in layman terms

    Does the below sound ok? 1. Interference is caused between coherent waves 2. When we try to find which-way we break the coherence a) When we try to "partially" find which way, we partially break the coherence and hence a "partial" interference pattern 3. DCQE is explained by the fact...
  42. P

    Mathematica Mathematica: take derivative in terms of original function

    Hello, Let's say we have f[x_,y_]:= whatever then we say expr1 = D[f[x,y],x] which is some complicated expression. How can we get the answer in terms of f[x,y]? That is, how can we get expr1 to look like: expr1 = f[x,y]*this term + pi*Sqrt[f[x,y]] + et cetera? Thanks Gurus
  43. H

    Express the components of Fμν in terms of E and B

    Homework Statement Express the components of Fμν in terms of E and B.Homework Equations I have find sonewhere the final 4*4 matrix solution but i don't know what are the steps i have to follow in order to obtain it. The Attempt at a Solution
  44. J

    Why is it that neutrino oscillations are allowed to happen in terms of energy?

    If I'm not mistaken, the 3 flavours of neutrino are supposed to have different masses, right? Why then, if you had, say, an electron neutrino traveling along with a certain value of (kinetic + mass) energy, and then it oscillates into a muon neutrino with a different mass, could that be allowed...
  45. C

    Mathematica Mathematica: Putting an expression in terms of a specific variable

    My problem is this: I have an algebraic expression, and I want to express it in terms of one variable divided by another. It's a fairly large expression, and I'd like to do it in mathematica before attempting it by hand. I've tried Simplify, FullSimplify and Solve, but none of these have done...
  46. K

    What do uniaxial and biaxial mean in relation to piezoelectric film development?

    Ok. I know this may sound like a stupid question but for the life of me i can't find definitions for these terms. I am working on developing a PVDF polymer based piezoelectric film and need to know what the terms Uniaxial and biaxial mean. I am using an electrospining method to make the fibers...
  47. K

    What does Activity mean in terms of radioactive decay?

    What does "Activity" mean in terms of radioactive decay? I came across this term "activity" in text regarding radioactive decay and half lives. It is defined as "number of nuclei in a sample that decay within a given time." That definition if fine but then when presented in a graph life...
  48. J

    Solving for x in a Trigonometric Equation

    Homework Statement Sin x / x = 1/ (2)^1/2 how do I solve for x? I know x is 1.392 The Attempt at a Solution I thought I might be able to use some series expansion, but it gets quite messy. Help please?
  49. L

    Anybody here who could explain to me in the simplest terms what is so

    Anybody here who could explain to me in the simplest terms what is so special about the Lie group SO(8) and what is meant by triality? I know some Lie and representation theory, mostly from physics books. As I understand there are vector and spinor representations for so(n). If n is even...
  50. J

    Expressed in terms of the constants

    Homework Statement "Expressed in terms of the constants in this model, how high is the lowest point of the cable? (Assume the correct dimension to be in metres)"Homework Equations Equation for the shape of a hanging cable. [PLAIN]http://img59.imageshack.us/img59/8672/eqn6142.png edit: P, g...
Back
Top