Partial Definition and 1000 Threads

  1. R

    Partial derivative and chain rule

    How is the double derivative equal to that in the equation 2 in the attachment? =|
  2. J

    Partial derivatives of 3D rotation vectors

    I am utilitizing rotation vectors (or SORA rotations if you care to call them that) as a means of splitting 3D rotations into three scalar orthogonal variables which are impervious to gimbal lock. (see SO(3)) These variables are exposed to a least-squares optimization algorithm which...
  3. MarkFL

    MHB Partial Fraction Decomposition Help - Calculus BC

    Here is the question: Here is a link to the question: Help with Calculus BC: partial fractions!? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.
  4. Mandelbroth

    What Do Partial Derivatives Tell Us in Thermodynamics and Beyond?

    In a thermodynamics question, I was recently perplexed slightly by some partial derivative questions, both on notation and on physical meaning. I believe my questions are best posed as examples. Suppose we have an equation, (\frac{\partial x(t)}{\partial t}) = \frac{1}{y}, where y is a...
  5. stripes

    Cesaro summability implies bounded partial sums

    Homework Statement Suppose c_{n} > 0 for each n\geq 0. Prove that if \sum ^{\infty}_{n=0} c_{n} is Cesaro summable, then the partial sums S_{N} are bounded. Homework Equations -- The Attempt at a Solution I tried contraposition; that was getting me nowhere. I have a few...
  6. S

    Problem resolving an Integral - Partial Fractions

    1. So, i have the next integrand... 2. \int \frac{1}{(x-1)^2(x+1)^2}\,dx 3. I proceeded by resolving it by partial fraction and i came up with the next... \int \frac{1}{((x-1)^2)((x+1)^2)}\,dx = \int \frac{A}{(x-1)} + \frac{B}{(x-1)^2} + \frac{C}{(x+1)} + \frac{D}{(x+1)^2}\,dx The thing is...
  7. trollcast

    Partial Fractions: Solving 2x^2/(1-x(1+x))

    Homework Statement Use the method of partial fractions to show that: $$\frac{2x^2}{(1-x(1+x)} $$ , may be written as: $$-2+\frac{1}{1-x}+\frac{1}{1+x}$$ , where $$\lvert x\rvert\neq1 $$. Homework Equations The Attempt at a Solution I obviously know how to do it but in the...
  8. Greg Bernhardt

    Calculus Basic Partial Differential Equations by D. Bleecker and G. Csordas

    Author: David Bleecker (Author), George Csordas (Author) Title: Basic Partial Differential Equations Amazon Link: https://www.amazon.com/dp/1571460365/?tag=pfamazon01-20 Prerequisities: Table of Contents: Preface Review and Introduction A Review of Ordinary Differential Equations...
  9. P

    Partial derivative chain rule for gradient

    Homework Statement compute the gradient: ln(z / (sqrt(x^2-y^2)) Homework Equations ∇=(∂/(∂x)) + ... for y and z I just want to know how to do the first term with respect to x The Attempt at a Solution I am so rusty I don't know where to begin.
  10. U

    Partial differentiation: prove this general result

    Homework Statement The function f(x,y,z) may be expressed in new coordinates as g(u,v,w). Prove this general result: The Attempt at a Solution df = (∂f/∂x)dx + (∂f/∂y)dy + (∂f/∂z)dz dg = (∂g/∂u)du + (∂g/∂v)dv + (∂g/∂w)dw df = dg since they are the same thing? but the...
  11. P

    General solution of a system of equations and partial fractions

    I've been trying to get out this question for a while now: ai) Show that (x,y,z) = (1,1,1) is a solution to the following system of equations: x + y + z = 3 2x + 2y + 2z = 6 3x + 3y +3z = 9 aii) Hence find the general solution of the system b) Express 2x^2 + 3/(x^2 + 1)^2 in partial...
  12. H

    How are partial differential equations used to model physical systems?

    Plese give me silminer simple example or anther example on this case or explein the steps
  13. J

    How to integrate this partial differential equation

    I have the following equation \frac{\partial}{\partial y}\left(m\frac{dy}{dx}\right)=0 where y is a function of x and m is a function of y. If I integrate this equation first with respect to y should I get a function of x as the constant of integration (say C\left(x\right)) or it is just...
  14. O

    MHB Calculating partial derivatives in different coordinate systems

    let f = x2 + 2y2 and x = rcos(\theta), y = rsin(\theta) . i have \frac{\partial f}{\partial y} (while holding x constant) = 4y . and \frac{\partial f}{\partial y} (while holding r constant) = 2y . i found these partial derivatives by expressing f in terms of only x and y, and then in...
  15. U

    Finding the Implicit Partial Derivative (∂y/∂x)z for x3 + y3 + z3 - 3xyz = 6

    Homework Statement x3 + y3 + z3 - 3xyz = 6 Find (∂y/∂x)z. Homework Equations [b]3. The Attempt at a Solution [/ can i simply take the partial derivative of both sides treating z as constant? x3 + y3 + z3 - 3xyz - 6 = 0 f(x,y,z) = 0 (∂f/∂x)z = 0
  16. Y

    Commutative property of partial derivatives

    Hi everyone, I am working on simplifying a differential equation, and I am trying to figure out if a simplification is valid. Specifically, I'm trying to determine if: \frac{\del^2 p(x)}{\del p(x) \del x} = \frac{\del^2 p(x)}{\del x \del p(x)} where p(x) is a function of x. Both p(x)...
  17. J

    Manipulation of partial differential operators.

    Homework Statement Given that u(x,y) and y(x,z) are both continuous, differentiable functions show that (\frac{\partial u}{\partial z})x=(\frac{\partial u}{\partial y})x(\frac{\partial y}{\partial z})x Homework Equations Only equations given above The Attempt at a Solution I...
  18. A

    Determine whether a function with these partial derivatives exist

    Homework Statement Determine whether a function with partial derivatives f_x(x,y)=x+4y and f_y(x+y)=3x-y exist. The Attempt at a Solution The method I've seen is to integrate f_x with respect to x, differentiate with respect to y, set it equal to the given f_y and show that it can't be...
  19. T

    Help With Partial Derivatives and Infinite Sums

    I'm working on a calculus project and I can't seem to work through this next part... I need to substitute equation (2) into equation (1): (1): r\frac{\partial}{\partial r}(r\frac{\partial T}{\partial r})+\frac{\partial ^{2}T}{\partial\Theta^{2}}=0 (2): \frac{T-T_{0}}{T_{0}}=A_{0}+\sum from n=1...
  20. M

    System of non-linear partial differential eqs from electrostatics

    I have an electrostatics problem (shown here: https://www.physicsforums.com/showthread.php?t=654877) which leads to the following system of differential equations: \frac{\partial E_z}{\partial z}=\frac{\rho}{\epsilon_0} (1) Z_i E_r \frac{\partial \rho}{\partial r}+(u_g+ Z_i E_z)...
  21. Kushwoho44

    Not sure what square brackets indicate when dealing with partial derivates

    Hi guys, attached is a picture of my problem and it is also underlined. I've been reading through this theory and I just don't understand what the square brackets indicate. I understand that ∇phi is the partial derivative with respect to the scalar function phi. But what is ∇phi...
  22. D

    Partial differential equation, characteristic equations.

    Homework Statement Given the initial value problem: \frac{(u)}{(1-e^-(2x))}u_{x}+ \frac{\sqrt{t}}{u}u_{t}=1, with x, t, u > 0 Subject to condition u(x,1)=e^{-x} Homework Equations a) Classify given partial differential equation. b) Write the characteristic equations. By...
  23. M

    How to Simplify Partial Fraction Decomposition with Complex Roots?

    Homework Statement How to get partial fraction decomposition for \frac{1}{(x^2+a^2)(x^2+p^2)}Homework Equations The Attempt at a Solution I tried with \frac{1}{(x+ia)(x-ia)(x+ip)(x-ip)}=\frac{A}{x+ia}+\frac{B}{x-ia}+\frac{C}{x-ip}+\frac{D}{x+ip} and get the result at the end of the day. Is...
  24. Y

    Equilibrium Partial Pressure Kp/Kc Question

    Homework Statement At 100 o C Kc=.078 for the reaction SO2Cl2<-->SO2 + Cl2. In an equilibrium mixture the [SO2CL2]=.0108 M and [SO2]=.052 M. What is the partial pressure of Cl2 in the eq. mixture? Homework Equations Kp=Kc(RT)\Deltan P=RT/V The Attempt at a Solution I solve for...
  25. D

    Dx and delta(x) (in partial derivative)

    I have a question to ask, is dx = δx, can they cancel each other like \frac{dx}{δx}=1 and is it mean that: \frac{δf}{δx}\frac{dx}{dt}=\frac{df}{dt}? (f = f (x,y,z))
  26. Jalo

    Partial differentiation - Constants

    Homework Statement Consider the following equality: (\frac{∂S}{∂V})T = (\frac{∂P}{∂T})V If I rearrange the equality so that I write: (\frac{∂S}{∂P})? = (\frac{∂V}{∂T})? What variables will be constant in each side? I'm having some trouble in a few thermodynamics problems because...
  27. Jalo

    Archived Partial Derivatives and Constant Variables in Thermodynamics

    Homework Statement Consider the following equality: (\frac{∂S}{∂V})T = (\frac{∂P}{∂T})V If I rearrange the equality so that I write: (\frac{∂S}{∂P})? = (\frac{∂V}{∂T})? What variables will be constant in each side? I'm having some trouble in a few thermodynamics problems because...
  28. M

    Partial derivatives after a transformation

    Suppose I have a transformation (x'_1,x'_2)=(f(x_1,x_2), g(x_1,x_2)) and I wish to find \partial x'_1\over \partial x'_2 how do I do it? If it is difficult to find a general expression for this, what if we suppose f,g are simply linear combinations of x_1,x_2 so something like ax_1+bx_2 where...
  29. M

    Partial Derivative of atan(xy/(1+x^2+y^2)^0.5)

    Homework Statement Prove that if ##z=\arctan(\frac{xy}{\sqrt(1+x^2+y^2)})## , then: ##\frac{\partial^2 z}{\partial x \partial y}=\frac{1}{(1+x^2+y^2)^\frac{3}{2}} ## Homework Equations ##\frac{d}{d x} (\arctan(x)) = \frac{1}{1+x^2}## The Attempt at a Solution Differentiating z...
  30. W

    Proving partial deviatives not continous

    Homework Statement f(x,y) = y^2 + (x^3)*sin(1/x) when x =/= 0 = y^2 when x = 0 i want to prove fx(x,y) is not continuous at (0,0) Homework Equations The Attempt at a Solution i found when x=/=0 , fx = 3(x^2)sin(1/x) - xcos(1/x) -----eq(1)...
  31. E

    Partial Derivatives - Basic Formula

    Could someone please explain how the formula at the bottom of the page is derived i.e. how is the Taylor theorem used to obtain it ?
  32. D

    Partial sum for series, sum of cubes

    Homework Statement I have this series 1^{3}-2^{3}+3^{3}-4^{3}+5^{3}-6^{3} + \ldots Homework Equations and sequence of partial sums for this series that is: S_n = \sum_{k=0}^{n}(-1)^{k+1} k^3 = \dfrac{1 + (-1)^n(4n^3 + 6n^2-1)}8 =\begin{cases} \dfrac{2n^3+3n^2}4; & n \text{ is...
  33. R

    Partial differential = the change?

    partial differential = the change?? Homework Statement How is Δy/Δx = \partial y / \partial x ? I just don't know the logic behind this.
  34. E

    Partial Derivative Product with variables as functions

    Homework Statement I'm trying to understand how a certain substitution can be made with regards to taking the partial derivative of a function product when the variable I am differentiating by is a function itself.Homework Equations (∂/∂p) (v(p)p(x,t)) = v(p) + (∂v/∂p)pThe Attempt at a...
  35. K

    Linear Partial Differential Equations

    Just curious if anyone has any good recommendations for books or resources on Linear Partial Differential Equations. Thanks.
  36. B

    Measurning the partial pressure of a component of a solution in equilibrium

    Homework Statement Suppose I have two substances in a solution, each forming an equilibrium with its corresponding vapor phase, and thus having its own partial pressure. How can I measure this partial pressure of one of the components, given the pressure of each component in its pure form...
  37. O

    Partial differential of U at constant temperature?

    U is internal energy T is temperature v is volume U(T,v) My book say (∂u/∂v) at constant temperature can be calculated from the equation of state. How to calculate it? Thank you
  38. J

    Integration by partial fractions?

    Whoa, this here is kicking me hard! Okay, so I've got everything pretty well down until... stuff like... \int \frac{3x + 32}{x^{2}-16x + 64}dx So, I get how to factor the denominator, but then what? The above won't factor... Also, I read that if the degree of the numerator is higher than the...
  39. A

    Partial Pressure Quest: 2L Vessel, PCl5 Decomposition @ 250C

    We have an empty vessel with volume of 2L. We put 2.42gr of PCl5 (g) and allowed it to partially decompose at 250 Celsius according to: PCl5 --> PCl3 + Cl2 the two prodcuts are also gases. The total pressure inside the vessel after this partial decomposment is 359 torr. What is the partial...
  40. T

    Can f(x, t) be expressed as a function of x + ct?

    Homework Statement Suppose f: R^2 --> R is differentiable and (df/dt) = c(df/dx) for some nonzero constant c. Prove that f(x, t) = h(x + ct) for some function h. Homework Equations hint: use (u, v) = (x, x+ct) The Attempt at a Solution df/dt = limk-->0 (f(x, x+ct+k) - f(x...
  41. T

    Directional derivatives and partial derivatives

    Homework Statement Suppose f: R -> R is differentiable and let h(x,y) = f(√(x^2 + y^2)) for x ≠ 0. Letting r = √(x^2 + y^2), show that: x(dh/dx) + y(dh/dy) = rf'(r) Homework Equations The Attempt at a Solution I have begun by showing that rf'(r) = sqrt(x^2 + y^2) *...
  42. P

    I don't understand how partial derivatives work exactly

    what does d/ds (e^s cos(t)du/dx + e^s sin(t)du/dy) give, given that u = f(x,y) i don't know how to manipulate d/ds and how to derive using d/ds. i am trying to simplify the expression, but i don't know, i just get stuck in the middle of can't get farther than here...
  43. P

    Partial derivative chain rule proof

    Homework Statement If u=f(x,y) where x=escost and y=essint show that d2u/dx2+d2u/dy2 = e-2s[d2u/ds2+d2u/dt2 Homework Equations http://s11.postimage.org/sjwt1wkvl/Untitled.jpg The Attempt at a Solution ok i don't understand how they got to that i don't know what d/ds is...
  44. P

    Partial derivative query - guidance needed

    I have a question but have not seen an example or find anything in my textbooks so would love some advice on how to understand the problem. Its a theory question on partial derivatives of the second order... T=T(x,y,z,t) with x=x(t), y=y(t), z=z(t). Find the second derivative of T wrt t So...
  45. B

    Solving Partial Fractions with Polynomial Division

    Homework Statement ∫ (x^3)/(x^2+2x+1) I think I could solve it if I knew how they did this operation: From the solution: ' (x^3)/(x^2+2x+1) = (x-2) + (3x+2)/(x+1)^2 ( After long division) Did they use polynomialdivision? x^3: x^2-2X+1= If so, how?
  46. P

    What are the partial limits of cos(pi*n/3)?

    Hi, Trying to find all partial limits of cos(pi*n/3), I separated it into: a_3k -> -1 a_6k -> 1 Is this a valid approach? Are there any other partial limits?
  47. E

    Why is there an S attached to D in partial fractions for Laplace transforms?

    Homework Statement Hi I just have a problem in regards to setting up your partial fractions when doing nonhomogeneous differential equations using Laplace transforms. I’m at the stage of getting the inverse Laplace of: (1-625S^4)/(S^3 (25S^2+1) ) Homework Equations The Attempt...
  48. B

    Laplace equation w/ dirichlet boundary conditions - Partial Diff Eq.

    Homework Statement The steady state temperature distribution T(x,y) in a flat metal sheet obeys the partial differential equation: \displaystyle \frac{\partial^2 T}{\partial x^2}+ \frac{\partial^2 T}{\partial y^2} = 0 Seperate the variables in this equation just like in the...
  49. E

    Meaning of in partial fulfillment

    Meaning of "in partial fulfillment" In a thesis one often finds this sentence: "A thesis submitted in partial fulfillment of the requirements for the degree of... ", e.g. here: http://dmg.caup.washington.edu/pdfs/Thesis.HunterRuthrauff.2012.pdf What does "in partial fulfillment" mean, in...
  50. F

    Partial differential problem in introductory tensor analysis

    So far I have only seen ∂/(∂y) as being interpreted as an operator being of no use unless it is applied to some vector etc. Now, however, my course literature asserts the following equality: y=∂/(∂y) What is the interpretation of the differentials in this case?
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