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1
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1answer
80 views

Derivative of a plot [on hold]

I plotted a graph numerically, so I don't have a definition of the plotted function. Now I want to plot the derivative of this graph. Is there any way to do it in Mathematica? I have the following ...
6
votes
1answer
175 views

Better replacement rules to perform this change of variables?

In cosmology, it is common to work with both a normal time variable t and a “conformal” time variable τ, which is defined such ...
0
votes
1answer
41 views

Differentiating an equation [closed]

Hi all I need to differentiate an equation: K = a*b*(c-h)^2*(2*c+h)*PI()/(3*c*c) I need to find dK/dh. How do I evauate this in mathematica? is this correct? ...
1
vote
1answer
53 views

How to compute the composition of linear differential operator [duplicate]

For example, I have to write down the differential operator below as a polynomial in $\partial$ $$(\partial-f_n(x))(\partial-f_{n-1}(x))\cdots(\partial-f_1(x))$$where the product the the composition. ...
0
votes
0answers
44 views

Determination of Ricci tensor and Scalar curvature from veirbeins

Consider the following metric: $ds^2=h(r)\bigg(dr^2+r^2\big(d\theta^2+\sin^2\theta ~d\phi^2+(d\psi+\cos\theta ~d\phi)^2\big)\bigg)$ We can try to compute the Ricci scalar of this metric by using ...
0
votes
1answer
64 views

Differentiating two tables x and y?

I have two tables x and y with x={673,674,675,...} and y={0,1,2,...} and delta=dx/dy. I would like to know how delta can be calculated knowing that delta is the derivative of x divided by the ...
6
votes
1answer
89 views

Taking the derivative of a function with indexed variables

I have a number of functions that depend on a variable x. I am using a second, integer variable to index these functions, i.e. something like ...
1
vote
1answer
44 views

Specifying independence of a variable in a function

I am dealing with a function of a finite number of variables and among the operations I wish to do is to differentiate it repeatedly with respect with any of the variables. Now this function happens ...
0
votes
1answer
49 views

What's the difference between this differentiation? [closed]

I've tried to evaluate a sum and get a result in terms of Zeta function. And I have results in two forms: ...
2
votes
1answer
201 views

Solve ODE $d^2u/dx^2 + u/A = 0$

How can I solve following ODE with Mathematical: $$d^2u/dx^2 + u/A = 0 \quad (\text{or } \ C),$$ with the conditions: $$ \left.\frac{d^2u}{dx^2}\right|_{x=0} = 0, $$ $$u(x=0) = B$$ and ...
1
vote
1answer
60 views

Differentiation of Vector Equation

Is it possible to get symbolic derivatives of equations with vectors as arguments without specifying every vector element explicitly. Something like ...
4
votes
1answer
160 views

Mathematica package for supergravity and superstring theory

I am looking for a Mathematica package that can manipulate tensors for supergravity, string theory or M-theory. I am particularly looking for a package that can do spinor and Clifford algebra ...
1
vote
2answers
55 views

Simple derivative not working [closed]

I'm a complete newbie to Mathematica. I've been using Wolfram Alpha Pro as well as MS Mathematics for a few months but wanted to dive into using a more powerful tool. I'm having a problem with ...
0
votes
1answer
72 views

Unable to configure a system of differential equations

My differential equations have been written as ...
1
vote
0answers
116 views

Extract coefficients of differential form in package RGTC

I am using the Package RGTC to do some calculations in Supergravity. It allows to define differential forms after specifying a co-frame. I am working in with the 10d coordinates ...
0
votes
1answer
63 views

Using Derivative with list in curly brackets

I'd like to make a formula for a sum containing Derivative where the number of arguments in the latter depends on an input parameter n. Also involved is a list ...
0
votes
0answers
38 views

Using derivative d in Mathematica [duplicate]

In mathematics derivates are often written like $$d^2y \over dx^2$$ or $$dy \over dx$$ In Mathematica we have the function D, but is it possible to use a similar approach?
8
votes
1answer
307 views

Inconsistent results of second derivative of inverse fourier transform

I am trying to get the Green's function of a toy diffusion equation $$\frac{\partial^2 u(x,t)}{\partial x^2} = \frac{1}{\alpha^2}\frac{\partial u(x,t)}{\partial t}$$ with Mathematica 9. Then solve ...
5
votes
1answer
113 views

Apparently contradictory output from Series and D

I defined a function as: g[b_] := Integrate[f[n]Exp[-b DA (n.u)^2], n] Obviously D[g[b], b] /. b -> 0 gives ...
3
votes
2answers
167 views

Differentiating a Cumulative Distribution Function which has a discontinuity at $0$

I want to take the derivative of a distribution function which has a discontinuity at $0$. Here is the function: ...
1
vote
1answer
266 views

Solve a total derivative - independent vs. dependent variables

I am trying to force mathematica to solve a generally defined function for d lp: In a reduced version, w depends on l2, ...
1
vote
3answers
2k views

Find dy/dx given an equation

Here's a homework problem from the Coursera course Calculus: Single Variable by Robert Ghrist Find the derivative $\frac{dy}{dx}$ from the equation $x \tan y - y^2 \ln x=4$ I wanted to check my ...