Partial Definition and 1000 Threads

  1. Naeem Anwar

    Main difference between P, S & D Partial Waves in Decays?

    I am a little confused about; how to identify that Hadron/Meson may have S, P or D wave contribution to its decay to other hadrons. e.g in case of light meson decay a1→ ρπ this decay channel have two partial...
  2. I

    Error propagation - partial derivative?

    I am getting a little confused on which error propagation to use: I am looking to calculate the error in B*Cos(θ) , for the vertical axis of a williamson hall plot. where B is fwhm of a peak with it's own error and cos of the bragg angle I am unsure of whether i need to use partial derivative...
  3. binbagsss

    E+e- collison Resonance peaks cross-section partial widths

    Question: The Breit-Wigner cross-section for a resonance R is ## \sigma_{i \to f} =12\pi\frac{\Gamma_{R\to i} \Gamma_{R\to f}}{(s-M^{2})^{2}+M^{2}_{R}\Gamma^{2}_{R total}}## [1], where ##s## is the com energy squared, ##M_{R}## is the mass of the resonance , ##\Gamma_{R total}## is the total...
  4. P

    Partial Fractions: Decomposing a Rational Function

    Suppose we have a rational function ##P## defined by: $$P(x) = \frac{f(x)}{(x-a)(x-b)}$$ This is defined for all ##x##, except ##x = a## and ##x = b##. To decompose this function into partial fractions we do the following: $$\frac{f(x)}{(x-a)(x-b)} = \frac{A}{x-a} + \frac{B}{x-b}$$ Multiplying...
  5. StrangeCharm

    Integration by Partial Fractions Help

    Homework Statement ∫ [x^(3)+4] / [x^(2)+4] dx Homework Equations N/A The Attempt at a Solution I know that the fraction is improper, so I used long division to rewrite it as x+(-4x+4)/[x^(2)+4]. Given the form S(x)+R(x)/Q(x), Q(x) is a distinct irreducible quadratic factor [x^(2)+4]. I used...
  6. M

    Chain Rule with Partial Derivative?

    Homework Statement Given that the surface x^7y^2+y^4z^6+z^8x^8+9xyz=12 has the equation z=f(xy) in a neighbourhod of the point (1,1,1) with f(x,y) differentiable, find the derivatives. df/dx (1,1) = ? d^2f/dx^2 (1,1) = ? Homework EquationsThe Attempt at a Solution df/dx (1,1) I got -24/23 or...
  7. kostoglotov

    Partial Derivative Q: continuity and directional deriv's

    Homework Statement a) Show that the function f(x,y)=\sqrt[3]{xy} is continuous and the partial derivatives f_x and f_y exist at the origin but the directional derivatives in all other directions do not exist b) Graph f near the origin and comment on how the graph confirms part (a). 2. The...
  8. powerof

    Symmetry in second order partial derivatives and chain rule

    When can I do the following where ##h_{i}## is a function of ##(x_{1},...,x_{n})##? \frac{\partial}{\partial x_{k}}\frac{\partial f(h_{1},...,h_{n})}{\partial h_{m}}\overset{?}{=}\frac{\partial}{\partial h_{m}}\frac{\partial f(h_{1},...,h_{n})}{\partial x_{m}}\overset{\underbrace{chain\...
  9. nuuskur

    What is the partial derivative of f(x,y) with respect to x if y=0?

    Homework Statement Find \frac{\partial}{\partial x} if: f(x,y) = \begin{cases}x^2\frac{\sin y}{y}, & y\neq 0\\0, &y=0 \end{cases} Homework EquationsThe Attempt at a Solution If y\neq 0 , then it's simple, but I get confused about the second part. How can I exactly utilize the limit definition...
  10. M

    Equations of state -- Partial derivatives & Expansivity

    Homework Statement Show that the coefficient of volume expansion can be expressed as β= -1÷ρ (∂ρ÷∂T) keeping P (pressure) constant Where rho is the density T is Temperature Homework Equations 1/v =ρ β= 1/v (∂v÷∂T) keeping P (pressure ) constant The Attempt at a Solution I started with...
  11. V

    Multivariate piecewise fxn continuity and partial derivative

    1. Problem Define a function: for t>=0, f(x,t) = { x for 0 <= x <= sqrt(t), -x + 2sqrt(t) for sqrt(t) <= x <= 2sqrt(t), 0 elsewhere} for t<0 f(x,t) = - f(x,|t|) Show that f is continuous in R^2. Show that f_t (x, 0) = 0 for all x. Then define g(t) = integral[f(x,t)dx] from -1 to 1. Show...
  12. kostoglotov

    Partial derivatives Q involving homogeneity of degree n

    Homework Statement Show that if f is homogeneous of degree n, then x\frac{\partial f}{\partial x} + y\frac{\partial f}{\partial y} = nf(x,y) Hint: use the Chain Rule to diff. f(tx,ty) wrt t. 2. The attempt at a solution I know that if f is homogeneous of degree n then t^nf(x,y) =...
  13. D

    Proving the reciprocal relation between partial derivatives

    If three variables x,y and z are related via some condition that can be expressed as $$F(x,y,z)=constant$$ then the partial derivatives of the functions are reciprocal, e.g. $$\frac{\partial x}{\partial y}=\frac{1}{\frac{\partial y}{\partial x}}$$ Is the correct way to prove this the following...
  14. M

    Ordinary or partial differential equation

    Homework Statement x(d^2y/dx^2)+dx/dt+xy=0 Homework EquationsThe Attempt at a Solution At first I thought it was an ODE, but then I found out the derivative was respect to to variables x and t. I am not sure if it is an ODE or PDE. What are the dependent and independent variables in the...
  15. RJLiberator

    Partial Derivatives and Polar Coordinates

    Homework Statement Write the chain rule for the following composition using a tree diagram: z =g(x,y) where x=x(r,theta) and y=y(r,theta). Write formulas for the partial derivatives dz/dr and dz/dtheta. Use them to answer: Find first partial derivatives of the function z=e^x+yx^2, in polar...
  16. I

    Partial Derivatives Homework: w(u,v)=f(u)+g(v)

    Homework Statement let w(u,v) = f(u) + g(v) u(x,t) = x - at v(x,t) = x + at show that: \frac{\partial ^{2}w}{\partial t^{2}} = a^{2}\frac{\partial ^{2}w}{\partial x^{2}} The Attempt at a Solution w(x-at, x+at) = f(x-at) + g(x+at) \frac{\partial }{\partial t}(\frac{\partial w}{\partial...
  17. Calpalned

    Partial derivatives of level curves

    Homework Statement Let ##C## be a level curve of ##f## parametrized by t, so that C is given by ## x=u(t) ## and ##y = v(t)## Let ##w(t) = g(f(u(t), v(t))) ## Find the value of ##\frac{dw}{dt}## Homework Equations Level curves Level sets Topographic maps The Attempt at a Solution Is it true...
  18. QuantumCurt

    Integral with partial fractions

    Homework Statement I'm currently in Calculus 3, and the professor gave us a "retro assignment" which is basically a bunch of tough integrals from Calculus 2. I think my process here is valid, but when I check my answer on Wolfram, they're getting a slightly different final answer...
  19. Calpalned

    Partial Derivative of w = xe^(y/z) | Homework Solution

    Homework Statement Find the partial derivative of ## w = xe^\frac {y}{z} ##. Homework Equations N/A The Attempt at a Solution ## \frac{∂f}{∂x} = e^y/z ## ## \frac{∂f}{∂y} = \frac{xe^y/z}{z} ## ## \frac{∂f}{∂z} = (-yz^-2)(xe^yz^-1) ## Are theses correct? Thanks everyone.
  20. Safinaz

    Partial decay width in Mathematica

    Hi there, I have a a partial decay width in form of ## \frac{d \Gamma}{d \cos{\theta}~ dq^2} = ## some terms functions in q and ## \theta ## variables. How to integrate this decay width in Mathematica over this two variables ? I tried some thing like j[q_]:= ## \int_{1}^{-1} ## Gam[q, ##...
  21. O

    How to reduce higher order partial differential equations

    Hello guys, I have the system of PDE below and I want to solve it using finite difference method but I think I have to reduce it first to a system of first order PDE. The problem is that I don't know how to reduce this PDE to a first order system. I will appreciate any hints in this regard...
  22. Calpalned

    What Is the Correct Partial Derivative of 6xyz?

    Homework Statement Find (∂z/∂x) of 6xyz Homework Equations N/a The Attempt at a Solution The correct answer is 6xy(∂z/∂x) but I would like proof of it. I got something different when I tried taking the partial derivative. 6xyz = 6x(yz) = Multiplication rule for derivatives 6(∂x/∂x) +...
  23. 462chevelle

    How Do You Integrate (x^2+x)/(x^2+x+1) from 0 to 1?

    Homework Statement integral(0>1) of (x^2+x)/(x^2+x+1)dx Homework Equations Factor denominator, and set numerator with A,B,C, etc. multiply both sides by the common denominator. The Attempt at a Solution Since the denominator won't factor at all I don't really know where to start, I could...
  24. B

    Equilibrium expressions and partial pressures

    Homework Statement In considering the reaction: 3NO (g) + H2O (l) → 2HNO3 (aq) + NO (g) student A writes the equilibrium expression as: K=[NO][HNO3]2/[NO2]3 while student B writes: K=PNO [HNO3]2/[NO2]3 Whose equation is correct? Homework Equations NA The Attempt at a Solution This is a...
  25. P

    Partial derivative of a square root

    Hi, I'm using partial derivatives to calculate propagation of error. However, a bit rusty on my calculus. I'm trying to figure out the partial derivative with respect to L of the equation: 2pi*sqrt(L/g) (Yep, period of a pendulum). "g" is assumed to have no error. I know I can use the...
  26. M

    Finding 2nd partial derivative

    I've attached an image to this post. It essentially shows the equation for the first partial derivative using chain rule, which makes sense. What I'm confused with is how the second partial derivative was formulated. It seems they've simply squared the first partial derivative to find the second...
  27. B

    What Is the Partial Pressure of Methyl Isonitrile After 12.8 Hours?

    Homework Statement The rate constant for the conversion of methyl isonitrile is 5 x 10^-5. A scientist has a container containing this substance with a partial pressure of 100 torr. After 12.8 hours (46,000 seconds), what is the partial pressure of methyl isonitrile gas inside the container...
  28. nmsurobert

    Partial derivatives and complex numbers

    Homework Statement show that the following functions are differentiable everywhere and then also find f'(z) and f''(z). (a) f(z) = iz + 2 so f(z) = ix -y +2 then u(x,y) = 2-y, v(x,y) = x Homework Equations z=x+iy z=u(x,y) +iv(x,y) Cauchy-Riemann conditions says is differentiable everywhere...
  29. E

    Understanding Partial Derivatives of x^2 + y^2 < 1

    Homework Statement x^2 + y^2 < 1 Find the partial derivatives of the function. Homework Equations x^2 + y^2 < 1 The Attempt at a Solution @f/@x = 2x = 0 @f/@y = 2y = 0 4. Their solution @f/@x = 2x = 0 @f/@y = 2y + 1 = 0 5. My Problem I don't see how / why they get 2y + 1 for the...
  30. nmsurobert

    Partial derivatives transformation

    Homework Statement Homework Equations included in the first picture The Attempt at a Solution i feel confident in my answer to part "a". i pretty much just did what the u and v example at the top of the page did. but for part "b" i tried to distribute and collect like terms and what not...
  31. A

    Density functional theory and partial charge transfer

    When density functional theory is used to simulate a molecule adsorbed on a surface, it turns out that due to their interaction, a fraction of an electron is transferred from the surface to the molecule or vice versa. These interactions are normally categorised in interactions involving...
  32. N

    Transforming Partial Differential Equations into Constant Coefficient Form

    Homework Statement The problem statement can be expressed in one of these forms listed in order of preference. [/B] Every character with exception of x, y, t, and C are constants. Homework Equations I require a change of variable or series of subsequent change of variables that can convert...
  33. D

    Partial Fractions: Why Does (x+1)2(2x+1) Need 3 Terms?

    Why, when a fraction has repeated linear terms in its denominator e.g. (11x2+14x+5)/[(x+1)2(2x+1)] does it have to be split into three partial fractions, A/(x+1) + B/(x+1)2 + C/(2x+1)? When my first saw this example, my initial reaction was to split it into A/(x+1)2 +B/(2x+1), but after working...
  34. T

    Possible partial waves for photoelectron of nitrogen

    Homework Statement (a) The nitrogen atom has seven electrons. Write down the electronic configuration in the ground state, and the values of parity (Π), spin (S), orbital angular momentum (L), and total angular momentum (J) of the atom. (b) If an extra electron is attached to form the N–...
  35. A

    Partial differentiation question rocket trajectory

    Homework Statement The problem and my attempt are attached Homework Equations Chain rule for partial differentiation perhaps And basic algebra The Attempt at a Solution I'm unsure of how to approach this but I differentiated all the expression at the top.
  36. G

    Hidden variables & partial correlations

    I recently understood Bell’s theorem (the inequality and the QM calculation), with the help of you guys. But something still bothers me: assuming for the moment that Bell’s inequalities were NOT violated by experiment, how we would we understand the dependence of the varying correlations on the...
  37. AwesomeTrains

    How Do You Calculate Partial Derivatives at a Singular Point?

    Homework Statement I want to find the partial derivatives in the point (0,0) of the function f:\mathbb R^2\rightarrow\mathbb R f(x,y):= \begin{cases} 0 & \text{if } (x,y) = (0,0) \\ \frac{y^5}{2x^4+y^4} & otherwise \end{cases} Homework Equations Our definition of the partial derivatives in...
  38. K

    Partial pressure of water vapor

    Homework Statement The partial pressure of water vapor in air at 200 is 10[mm] mercury. according to the table of partial pressures we have to cool the air to 11.40 in order to bring the air to saturation, that is100% relative humidity. this according to the book. But when we cool the pressure...
  39. S

    Inverse laplace transform without partial fractions

    Homework Statement take inverse laplace of: 6/[s^4(s-2)^2] Homework Equations 6/[s^4(s-2)^2] The Attempt at a Solution I used partial fractions. I was wondering if It could be manipulated to where I could use the laplace table?
  40. S

    How Does Temperature Change When Two Halves of a Heated Cylinder Are Rejoined?

    Homework Statement A very long homogeneous cylinder is cut in half along its axis. One half s than equally heated, while the other half is equally cooled. How does the temperature change when the two parts are joined back together, if the cylinder is well isolated? Homework EquationsThe...
  41. J

    Spherical coordinates of Partial Differential Equation

    Homework Statement I have a PDE and I need to solve it in spherical domain: $$\frac{\partial F(r,t)}{\partial t}=\alpha \frac{1}{r^2} \frac{\partial}{\partial r} r^2 \frac{\partial F(r,t)}{\partial r} +g(r,t) $$ I have BC's: $$ \frac{\partial F}{\partial dr} = 0, r =0$$ $$ \frac{\partial...
  42. END

    Partial Fraction Decomposition—Multiple Variables

    What's the best approach to solving the partial-fraction decomposition of the following expression? $$\frac{1}{(a-y)(b-y)}$$ The expression is not of the following forms: But I know the solution is $$= \frac{1}{(a-b)(y-a)}-\frac{1}{(a-b)(y-b)}$$
  43. T

    Partial Derivatives: Solving y^2=uy-v

    Hey, Little confused by something: if we have u=x+y and v=xy what is the partial derivative w.r.t. u of y^2=uy-v I am told it is 2y (dy/du) = u (dy/du) + y And I can see where these terms come from. What I don't understand is why there is no (dv/du) term, as v and u aren't independent...
  44. kq6up

    Best Guess for Partial Solution for Diff EQ?

    Homework Statement Find the specific solution for: y''-2y'+y=xe^x+4, y(0)=1, y'(0)=1. Homework Equations N/A The Attempt at a Solution Since xe^x is already in the general solution of the homogeneous version of this diff eq (complementary solution), my first guess for a partial solution...
  45. thegreengineer

    Directional derivative and gradient definition confusion

    Recently I started with multivariable calculus; where I have seen concepts like multivariable function, partial derivative, and so on. A week ago we saw the following concept: directional derivative. Ok, I know the math behind this as well as the way to compute the directional derivative through...
  46. F

    Partial Differentiation Question

    Homework Statement if z=\frac{1}{x^2+y^2-1} . Show that x \frac{\partial z}{\partial x} + y \frac{\partial z}{\partial y} = -2z(1+z) Homework Equations n/a The Attempt at a Solution I am extremely new to partial differentiation, I can get my head around questions where they just give...
  47. J

    Total derivative of a partial derivative

    Im doing a question on functionals and I have to use the Euler lagrange equation for a single function with a second derivative. My problem is I don't know how to evaluate \frac{d^2}{dx^2}(\frac{\partial F}{\partial y''}). Here y is a function of x, so y'=\frac{dy}{dx}. I know this is probably...
  48. S

    Multi-variable Calculus : Partial differentiation

    Homework Statement 2. The attempt at a solution By chain rule, which simpifies to, After this I am struck.
  49. M

    Electrochemical Cells (involving partial pressures and pH)

    Homework Statement A voltaic cell utilises the following reaction: 4 Fe2+(aq) + O2(g) + 4 H+(aq) ---> 4 Fe3+(aq) + 2 H2O(l) What is the emf of this cell when [Fe2+] = 1.3 M, [Fe3+] = 0.010 M, PO2 = 0.51 bar and the pH of the solution in the cathode is 3.5. The standard reduction potentials...
  50. P

    Partial Derivative Homework: Find ∂w/∂z and ∂^2w/∂y∂z

    Homework Statement If w = w(x, y, z) is given implicitly by F(x, y, z, w) = 0, find a formula for both ∂w/∂z and ∂^2w/∂y∂z . You may assume that each function is sufficiently differentiable and anything you divide by during the process of your solution is non-zero. The Attempt at a Solution I...
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