Partial derivative Definition and 374 Threads

  1. T

    Solving the Partial Derivative Equation: xy*z^2

    \frac{\partial z}{\partial x}\cdot \frac{\partial z}{\partial y}=xyz^2 People,do we know how to solve this? I'm looking for the explicite solution z=f(x,y) so far I'm unable to solve this .Thinking of it for a half a day without much of the progress.Even though I haven't tryed all dirty...
  2. V

    Mathematica Can Mathematica take the first, second, and third partial derivative?

    Does anybody know if Mathematica can take the first, second, and third partial derivatives of a function? If it can, how would I go about doing so?
  3. T

    Find Partial Derivative of f(x,y) w.r.t x

    f(x,y)=2y / (y+cos x) .Find partial derivative w.r.t x can someone teach me how to do this pls thanx
  4. T

    Partial Derivative of f(x) with Sin(x^2)

    f( x(1), ..., x(n) ) = sum (i=1) sin(x(i)^2) x(i) does anybody knows how to solve this pls
  5. T

    First Partial Derivative of f(x,y)=arctan (y/x)

    f(x,y)=arctan (y/x). may i know what is the first partial derivative of this?? thanx
  6. L

    Why is it important to specify constant variables in a partial derivative?

    Hi, What does it mean to put a partial derivative in first brackets and put a right subscript to it of another variable? (\frac {\partial Y} {\partial Y})_T Thanks. Molu
  7. F

    Some partial derivative questions

    I've have met partial derivatives and the \nabla symbol, however, I was asked today what was the geometrical representation and meaning of \nabla \times r and \nabla \cdot r where r was a surface in 3D (i.e. r(x,y,z) = ...). For the first one, I think that the answer might be: \left(...
  8. J

    What is the partial derivative of u with respect to t in terms of x, y, and t?

    This is annoying me as i have the answer on the tip of my pen, just can't write it down. I'm not 100% sure i understand what the question is asking me to do. Consider the quantity u = e^{-xy} where (x,y) moves in time t along a path: x = \cosh{t}, \mbox{ } y = \sinh{t} Use a method...
  9. E

    Partial Derivative of a Parametric Equation

    Hi, I'm getting confused over a few points on the derivative of a parametric equation. Say we the world line of a particle are represented by coordinates x^i . We then parametrize this world line by the parameter t. x^i = f^i(t) . Now here is where I get confused. The partial...
  10. P

    Partial Derivative Q: Is dV an Exact Differential?

    In determining if a function is exact, here is the question. If V=V(T,P) and PV+RT, show that dV = R/PdT - RT/P2 dP. Is dV an exact differential? Do I go about by taking the derivative of R/PdT with respect to T, etc? I know this is not a difficult function, but I just want to make sure I'm...
  11. P

    How to do this partial derivative

    I believe I have already found them for S and g, but I'm not sure how to do this for M2 and also M1 and M3.
  12. D

    Solving Partial Derivative Equation: Finding Error & Fixing It

    I'm trying to figure out this equation. {\Psi} = Ae^{-a(bx-ct)^2} I've expanded this to {\Psi} = Ae^{-ab^2x^2-abxct-ac^2t^2} When I try to find the derivative I get this \left(\newcommand {\pd}[3]{ \frac{ \partial^{#3}{#1} }{ \partial {#2}^{#3} } }...
  13. N

    Is the partial derivative for acceleration correctly solved?

    can anyone verify that the equations on the following page, http://nsr.f2o.org/equations.htm are corretly solved. The equations are used to find the uncertainity in the calculation of acceleration in my physics lab. The uncertinty (delta a) would be the sum of all of the four equations, which...
  14. S

    Help with this partial derivative problem

    I'm supposed to find (assume all these d's are the partial derivative sign, not d) d^2z/dxdy, d^2z/dx^2, and d^2z/dy^2 The one I can't do is z^2 + sinx = tany I set it equal to zero, so z^2 + sinx - tany=0 so dz/dx = - Fx/Fz = sec^2y/2z dz/dy = - Fy/Fz = -cosx/2z multiply them...
  15. Cyrus

    Is the Matrix Notation for Partial Derivatives Useful?

    A couple of quickies on the interpertation of the partial derivative I want to clear up with myself. If we have a parametric function: r(u,v)= x(u,v)i + y(u,v)j+z(u,v)k then the partial derivative W.R.T u or v is regarded as the tangent vector, and we can think of it as the speed, or...
  16. O

    Partial Derivatives Explained: Real-Life Examples and Solutions

    To me a derivative and a partial derivatice is the same thing. You just take it with respect to another vairable ... move some things around and solve... Can someone give me an example explainin what's happening... The difference between the two. I can solve it and i just absorb it , but...
  17. A

    Do we treat x and y as independent when differentiating f with respect to y?

    if you are given f(x,y)=x^2+y^2 and y=cos(t) x=sin(t), then when you differentiate f with respect to t, you use the partial derivatives of f with respect to x and y in the process. When i was taught partial derivatives, i was told that we "keep all but one of the independent variables fixed..."...
  18. J

    Need help on a partial derivative problem

    Find the second-order partial derivatives of the given function. In each case, show that the mixed partial derivatives f_{xy} and f_{yx} are equal. Function: f(x,y)=x^{3}+x^{2}y+x+4 My work (Correct me if I am wrong): \frac{\partial{f}}{\partial{x}}}=3x^{2}+2xy+1...
  19. W

    Total derivative -> partial derivative

    Under what conditions can you replace a total differential with a partial? dx/dy -> partial(dx/dy) in the context of 2 independant variables and multiple dependant variables. Thanks
  20. tandoorichicken

    What are the challenges of solving partial derivative problems in mathematics?

    Two homework problems I can't get. (1) The question is find the first partial derivatives of the function. The problem is that the function in this problem is f(x, y) = \int_{y}^{x} \cos{t^2} dt The main obstacle is getting past this function. I can't integrate it and neither can my...
  21. G

    Partial Derivative: Finding t with Respect to x | Step-by-Step Guide

    Hi All, Can someone refresh my memory and show me how to find the following partial derivate: t=\frac{x}{\sqrt{x^2+y^2}} with respect to x. Thanks
  22. S

    How do I solve this first order partial derivative problem?

    We went over this breifly in class and I'm confused on it. Were doing first order only and this is the problem: z = 3x^2*y^3*e^(5x-3y) + ln(2x^2 + 3y^3) I know your susposed to Fx(x,y) and treat X or Y as a constant, depending, upon how you want to start, but I'm still unclear as to how to...
  23. G

    Partial Derivative of f(x,y) = ∫xy cos(t2) dt?

    I need the partial derivatives of: f(x,y) = ∫xy cos(t2) dt are they simply: ∂f/∂x = -2xcos(x2) and ∂f/∂y = 2ycos(y2) or am I completely lost here?
  24. V

    A question about mixed partial derivative

    Let there be a function f[x,y]: RxR->R Is there any connection between the differentiability (I am not sure that this is the right English term - I meant f[x,y]= a*dx+b*dy +something of smaller order) and the equality fxy=fyx, where fxy means the derivative of f[x,y] first by y, and than...
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