## Error for the Vector constructor...

The following construction of a simple vector of matrices (just a test example)

`Vector(2,(a) -> Matrix(2,2,(b,c) -> m||a||b||c));`

works in Maple 17, but not in Maple 2017 where the error message "Error, (in Vector[column]) number of elements on right side must match subselection on left side" is produced. Why that?

Update: If no output is prompted, i.e., if the above line is terminated with colon instead of semicolon, then no error is raised. What?!

## Kinematics Curvilinear

Maple 18

With this application the components of the acceleration can be calculated. The components of the acceleration in scalar and vector of the tangent and the normal. In addition to the curvilinear kinetics in polar coordinates. It can be used in different engineers, especially mechanics, civilians and more.

In Spanish.

Kinematics_Curvilinear.mw

Lenin Araujo Castillo

## How to convert an imported data to Vector?...

A very big data was imported by me through

```data := Import("http://fs3.fex.net/get/245716150875/11071260/data.txt");
"3.0994584798345
22.889020258043
....

26.082759642081
42.911810680717
6.4578968130322"

```

I need to convert it to Vector/Array. Now its type is "string":

```whattype(data);
string
```

Here is my unsuccessful attempt:

```convert(data,Vector);
Error, invalid input: `convert/Vector` expects its 1st argument, V, to be of type {Array, Matrix, Vector, array, sequential}, but received 3.0994584798345
22.889020258043
....```

data.mw

## How do I solve a system in two unknown vectors?...

I'm trying to solve the really simple system u+v = <-2,4> and u-v = <-3,6> for u and v using Maple. My attempt attached.

Why do I get this error? How might I get the solution?

## Display a list of equations in column...

Hello,

I have a list of equations. I would like to display this list in column.
Problem : as each term of my list is an equation, i can not transform my list in a vector.
How can I do to display a list of equations in column ?

## Vectorization of Symbolic Functions...

Maple provides efficient vectorization and automatic parallelization for many common operators. For example

`x -> 2*~x*~cos~(x*~x)`

But in my application it is common to want to create rather long vectorized operators starting from some complicated symbolic computations. Doing conversions by hand from symbolic expressions to element-wise operations is laborious and error prone.

As a very simple example consider that it is possible to obtain (almost) the same result as above by writing the following as a vectorized operation

`D(x->sin(x^2))~`

But there are at least two problems with this. First of all it is not nearly as efficient as the first operator and second, perhaps not unrelated, is that the datatype returned when applying this operator to a Vector/rtable of hardware floats (e.g. datatype=float[8]) becomes something  more general.

My question is how can I convert a complicated symbolic expression into an efficient numeric element-wise vector operation?

I have tried several different approaches but so far without success. In the case above for example it seemed natural to expect that the following derivative

`D(x->sin~(x^~2))`

would produce a vectorized result, but this is not the case. In another attempt I was unable to see how to perform substitions into an expression, e.g. like this

`unapply(subs(`*`=`*`~, cos=cos~, diff(sin(x),x)), x)`

I would be glad to receive suggestions and/or references to relevant documentation.

## element by element vector multiplication...

I found the following:

Does this not apply to vectors?  If not what syntax is required?  I cannot seem to execute this simple operation which I can easily do in MATLAB.  If you have such a capability why is it not clearly documented in the HELP pages?

## Plot the eigenvalues of a matrix...

I want to plot the eigenvalues of a 4x4 matrix. I know how to determine the eigenvalues, but how do i plot them? Because i saw that plot only works with real numbers. The result is a column vector.

## Multiple surface intersection....

Hi.

Lets say im given 2 surfaces like this:

`S1: z=x^2+y^2 and S2: z=-2x`

To find all the points on this surface i set z=z and obtain the equation, but lets say I was given an arbutary vectorfield and was required to find the outward flux I would need and parametric equation for the surface which is now a solid enclosed by 2 surfaces.

Of course I could apply the divergence theoreme and integrate the divergens over the entire volume using tripple integral. This I suppose this requires a bit more work compared to using the vector calculus package.

Would anyone give me an hint on ho to acheive this? Im also looking to plot the object crated by the bounderies of the divergenc theorem bounderies

## defining a vector and store data in it, then writi...

I having a hard time with defining a vector, in order to store in it some data, then plot it and export it to a file, I copied all what's in the help instructures but it doesn't work everytime, please it's urgent for my PhD thesis !

## Maple help with lifting a vector...

Hej all,

I have a problem. When i have a 9-1 vector "DD" how can i get maple to solve DD^2 my equation is A=(pi/4)*DD^2 should be simple.

Also when i have two vectors one is 9-1 and the other is 5-1 i want to divide the 5-1 / 9-1 but i want all possible soluitons? not just 5 results but 45 results.(the zip fuction only gives me 5 results)

Pls help

Kind regards

## How to write the expressions in vectorial form?...

How do I convert an equation into a vectorial form in Maple?

Say you hav f_1(v)=-1/2*C*p*v*V

where V=[vx, vy] and v=|V|.

v=46m/s^2, A=18m^2, p=1,1

## Convolution of finite length vectors with arbitrar...

I attempted to use convolution in AudioTools to convolve 2 vectors with arbitrary values, but could not since the operation is expecting numeric values.  Can this be done?    Is there not a convolution operastor in the LinearAlgebra package?  See attached:

convolutionWithAu[1].mw

## How to plot in the same graph two sets of data poi...

Dear all,

I am trying to plot in the same graph two sets of data points given by vectors. Please see the example below. Any help will be highly appreciated. Thanks!

question.mw

## Angle larger as 180 degrees...

For a question for my students I want them to calculate tge resulting vector from two vectors. The student had to answer by giving the length and angle of the resulting vector.

For the question the vector angle is always larger as 180 derges, the student should for example give a result of 270 degrees.

Currently I'm using the following code:

\$F1=100;#range(200,500,20);
\$F2=100;#range(100,200,10);
\$A1=45;#range(10,80,5);
\$A2=45;#range(10,80,5);
\$A1r=180+\$A1;
\$A2r=360-\$A2;
\$F1x=maple("cos((\$A1r)*Pi/180)*\$F1");
\$F1y=maple("sin((\$A1r)*Pi/180)*\$F1");
\$F2x=maple("cos((\$A2r)*Pi/180)*\$F2");
\$F2y=maple("sin((\$A2r)*Pi/180)*\$F2");
\$V1=maple("Vector(2,[(\$F1x),(\$F1y)])");
\$V2=maple("Vector(2,[(\$F2x),(\$F2y)])");
\$V3=maple("(\$V1)+(\$V2)");
\$F3=maple("LinearAlgebra[Norm](\$V3)");
\$V0x=maple("Vector(2,[1,0])");
\$A3=maple("LinearAlgebra[VectorAngle]((\$V0x),(\$V3))");
\$A4=maple("evalf(((\$A3)*180/(Pi)))");

As you can see maple will always give an angle smaller than 180 degrees since the angle between two vectors is always 180 degrees or smaller.

Can anyone tell me how I should code this problem such that the rest for A4 will be 270 degrees rather than 90 degrees, as is given from the current way of coding.