1. W

    absolutely convergent series

    Hello. I want to show that, for an absolutely convergent series \sum_{n=1}^{\infty}a_n, we have \left|\sum_{n=1}^{\infty}a_n\right|\leq\sum_{n=1}^{\infty}|a_n|. Let M be an positive integer. I begin with the triangle inequality \left|\sum_{n=1}^{M}a_n\right|\leq\sum_{n=1}^{M}|a_n| and taking...
  2. P

    Solution of partial differential function.

    Dear all, I have the following Partial Differential Function. It's a Second-order variable coefficient homogeneous linear differential equation. (A.Y')+CY=0 in which A and Y are functions of x, C is a non-zero constant. A is not an elementary function. So is it possible to represent Y in...
  3. S

    Partial Differential Equation

    I am unable to solve the partial differential equation in the attached file. Please help me with the steps involved in solving this differential equation. It seems tough to me when applying the steps and procedures and I am unable to get the correct answer. :(:confused:

    Partial derivative

    Find \frac{\partial z}{\partial x} for x^{2}+\cos y +z^{3}=1 Please explain what it means.
  5. D

    Partial Differential Equation

    Help please, I need to solve this differential equation x\frac{\partial^2 U}{\partial x^2}+y\frac{\partial^2 U}{\partial y^2}=aU in Matlab (where "a" is a constant parameter, it can be taken by any), I wanted to use the Partial Differential Equation Toolbox, but I ran into a problem, the...
  6. SenatorArmstrong

    Academic Guidance Taking a class in partial differential equations

    I love math, but deep down physics is my true love in this life, but you can't do physics without math so my love for mathematics is definitely up there... I digress... I am wrapping up my undergraduate BS in physics, and getting ready for graduate school. I feel pretty good with basic...
  7. Newborn

    Partial Differential

    Hello, if f is a function of x, how come this is true: I could not remember this rule of partial differentiation. Any help? Thanks
  8. H

    Partial Differential Equation Mathematical Modelling

    Salutations, I have been trying to approach a modelling case about organism propagation which reproducing with velocity \alpha spreading randomly according these equations: $$\frac{du(x,t)}{dt}=k\frac{d^2u}{dx^2} +\alpha u(x,t)\\\ \\ u(x,0)=\delta(x)\\\ \lim\limits_{x \to \pm\infty} u(x,t)=0$$...
  9. M

    Partial derivatives

    Please could someone assist me with this question please I'm so lost. w=x^8+10xyz+y^9z^8 x=r^5-s^8 y=10rs z=5r-5s Find dw/ds and dw/dr
  10. H

    Intergral of a partial differential

    I need to have a step by step explaination of how the answer (ML/9EI) was achieved please.
  11. G

    Extrapolating a partial ordering

    Suppose we have a set S and an order \leq on most of the elements s_1,s_2 \in S. The problem is that the order is not defined for all pairs in S. Now how would I go and find an order \preceq on S such that s1 \preceq s2 if s1 \leq s2 and such that all elements of S are comparable for this...
  12. S

    ***Introduction To Partial Differential Equations.***

    Hi! What's your opinion about this book Introduction To Partial Differential Equations.: A Complete Course given in the following link : Thank you so much.
  13. M

    partial fraction decomposition

    My issue with this problem is that after factoring out an x, i get x^2-x+4 which gives me x(x^2-x+4). Normally i would factor it out but i can't do it normally, using quadratic equations which i was told not to do in class. Solving for a is easy enough, as i make x = 0 to cancel out B...
  14. C

    Need help with partial function problem.

    It's a problem from discrete math, not calculus. I don't know where else to post it though. Can someone please help me understand what exactly this question is asking me to do? "Show that a partial function from A to B can be viewed as a function f* from A to B U {u}, where u is not an element...
  15. SenatorArmstrong

    implicit partial differentiation

    Hello! This is an example problem in my textbook. I am stuck on understanding the second line. Everything makes absolutely perfect sense until they went ahead and tacked on that very last term the $+\,6xy\dfrac{\partial z}{\partial x}$. Perhaps the product rule was used? I am not sure. I...
  16. awholenumber

    Can someone show me some examples of partial differential equations ?

    Khan Academy is supposed to have some tutorial on partial differential equations, but instead I only found a YouTube video of PDE. I have never seen a differential equation containing partial derivatives LYsIBqjQTdI
  17. awholenumber

    What are partial differential equations?

    If the slope of the curve (derivative) at a given point is a number . :ninja:
  18. J

    Difference between partial and implicit differentiation

    Hi guys the question is: Find the equations of the tangent and normal lines to the curve 3x^2-14xy+8y^2-25=0 at the point P = (−1, 1). would i use partial or implicit differentiation here? Thanks !
  19. K

    Lebesgue-Stieltjes integrals, lower partial moments, probability distributions

    Working through a lecture in performance management course (topic about downside-oriented risk measures and lower partial moments), I have encountered several expressions of the following form: LPM(2,t)(R)=integral((t-R)^2dF(R))=E[(max{t-R;0})^2] where F(R) is the cumulative distribution...
  20. J

    Developing equation to satisfy specific parameters (potentially partial derivatives?)

    I'd like to start out by stating that I am an engineer, but would not consider myself a math expert. Which is why I am posting here; so I can pick the brains of those that eat and breathe this stuff (and are likely much smarter than me) :) I have a unique problem that I am trying to solve by...