Partial derivative Definition and 363 Threads

  1. 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} } }...
  2. 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...
  3. 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...
  4. 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...
  5. 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...
  6. 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..."...
  7. 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...
  8. 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
  9. 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...
  10. 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
  11. 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...
  12. 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?
  13. 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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