# Questions tagged [vector-calculus]

Questions on dealing with vector calculus functions of Mathematica such as Grad, Div, Curl, Laplacian and their representations in various coordinate systems.

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### Finding unit tangent, normal, and binormal vectors for a given r(t)

For my Calc III class, I need to find $T(t), N(t)$, and $B(t)$ for $t=1, 2$, and $-1$, given $r(t)=\{t,t^2,t^3\}$. I've got Mathematica, but I've never used it before and I'm not sure how to coerce ...
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### Symbolic derivatives with vectors and matrices

I'm currently trying to solve some problems using symbolic vectors and matrices of arbitrary size. However, I have some problems with understanding and verifying the results: I defined the vectors as ...
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### Quadratic form derivative in Mathematica

How to correctly differentiate quadratic form by vector in Mathematica, i.e.: $Q=\omega^T I_{p} \omega$ $\frac{dQ}{d\omega}= ???$ ...
274 views

### Visualizing combined Vectors

I'm trying to visualize a cross-section of a finite continuous solenoid's B-Field (cylindrical coordinate equations from Wikipedia). I believe I have calculated the radial and z-axis fields, but I'm ...
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### Creating randomly oriented planes

I would like to create randomly oriented planes. This is how I'm attempting to do that: I create a 2 random unit vectors, $\mathbf{v}_1$, and $\mathbf{v}_2$, in the $x$-$y$ plane I assume that if I ...
495 views

### How is Grad defined for array particularly in non-Cartesian coordinates?

This question can be viewed as a follow-up of What is the definition of Curl in Mathematica? First argument of Grad can be an array, but what definition does ...
1k views

### Finding surface normal for 3D region at a specific point

I would like to find the surface normal for a point on a 3D filled shape in Mathematica. I know how to calculate the normal of a parametric surface using the cross product but this method will not ...
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### How to calculate the surface integral of a vector field?

Suppose the oriented surface is described as, the outside of an upper hemisphere $S:x^2+y^2+z^2=1$ inside the cylinder $x^2-x+y^2=0$ The vector field is : ${\vec F}=<x^2,y^2,z^2>$ How to ...
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### Working with abstract vectors

I often need to compute derivatives or integrals involving N-dimensional vectors (where the dimension could be equal to 2 or 3 but is not particularly relevant for the sake of the derivation). The ...
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### Finding vector of same direction with smallest integer coordinates

To determine Miller Indices of crystal lattice planes I would need a stable algorithm which determines the smallest set of integer coordinates of a vector which has same direction as a given vector (e....
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### Get the vector Norm without absolute values? [duplicate]

I want to get the Norm of a vector which involves sines and cosines (So I really need to replace it by the Pythagorean theorem). Since I know that all my results are going to be real and positive I ...
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### Extending D for four-derivatives

I'm currently trying to consistently define rules for extending D[] to four-derivatives. As 'backend' I'm using the package TRACER (http://library.wolfram.com/infocenter/MathSource/2987/), which can ...
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### Checking if an expression is equal to zero

I have 6 points in $\mathbb R^3$ as follows: ...
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### How does one plot a three-dimensional electric field in spherical coordinates?

I have the following three-dimensional electric field: e[r_, θ_, ϕ_, t_] := (Sin[θ]/r)*(Cos[r - t] - Sin[r - t]/r)*{0, 0, 1} where the {0,0,1} vector is the unit ...
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### Manipulations with tensors that keep so(3,1) symmetry manifest

I am doing some manipulations with tensors in curved background. There are, however, coordinates, where Lorentz symmetry is manifest. So, on one hand, I am dealing with particular coordinates and, on ...
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### How are Symbolic Vectors Defined?

It is my understanding that undefined symbols are considered scalars, so I can't index variables that aren't defined. It is possible to define a symbol as a vector of symbols as follows, allowing ...
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### Plot a level curve and its gradient

Suppose that I have the following ellipse function, $f(x,y)=4x^2+y^2-5$. The gradient of this ellipse is calculated as $\nabla f(x,y)=[8x,2y]$. I know how to plot and join them. It is easy. I do ...
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### How do you show a cone inside of a sphere?

I have a sphere of radius 5 and a cone (i.e. z=√(x^2+y^2)) inside of it. I can show them separately, but I'd like to show them together. I've tried a few tricks with opacity, implicit specifications, ...