## How to find the condition on variables such that t...

Hi all,

I have the following expression,

where K and K_P are the controller gains, k is the stiffness, b is the damper, m1 and m2 are masses.

How can I find the condition on variables such that the numerator of this expression is greater that zero?

The conditions should appear as inequalities.

 (1)

## plotting a volume corresponding to the given inequ...

I have four spindle tori governed by the following equations:

I could plot the surfaces using implicitplot3d and I can imagine the volume common to these surfaces but I could not visualize it. So, am looking for a way to plot the volume covered by the surfaces such that f1<0, f2<0, f3<0 and f4<0. I know that it's easy in case of a 2D filled plot but is there any way this could be done for the 3D case? Any mathematical advice as to how to characterize or calculate this volume would also be great.

## Calculating components of acceleration in Maple

Maple 18

Using Maple's native syntax, we can calculate the components of acceleration. That is, the tangent and normal scalar component with its respective units of measure. Now the difficult calculations were in the past because with Maple we solved it and we concentrated on the interpretation of the results for engineering. In spanish.

Calculo_Componentes_Aceleracion_Curvilínea.mw

Lenin Araujo Castillo

## Roots of Bessel Functions zeros...

I want to find the i-th root of this equation s := BesselJ(1, alpha)+a1*BesselY(1, alpha)+b1*BeselJ(1, alpha)+c1*BesselK(1, alpha)

When I use the Nextzero it doesnt work

Thanks

## searching a value in a multi-dimensional list, arr...

Hi,

I couldn't find a command or tool for searching a value in a multi-dimensional list/array/matrix. Does it exist?.

I wrote this:

where

pSearch: proc for searching

A: list, array, vector or matrix

Examples with a list:

> ss := [[1, 2, 3], [2, 3, 5], [2, 4, 5]]
> j:=1:
># search first index i such that ss[i, j]=2

> nPos :=

# search next index i such that ss[i, j]=2

> nPos :=

But I am not sure if this procedure is efficient for large lists or arrays and I would suggest (if this tool does not exist yet) a more efficient one.

## When using . (DotProduct in VectorCalculus) I get ...

Pretty much the title.

At first I thought something's wrong with my vectors, but even something like <1,1,1>.<2,2,2> produces this error.

I have restart in the very beginning of my worksheet and with(VectorCalculus): right after.

I'm using the 64 bit version of Maple 18 on Windows 10, if this matters.

## how can save of resultes as matrix in file.dat?...

how can save of resultes as matrix in file.dat?

## How to convert maple file into pdf file?...

How to convert maple file into the pdf file?For example the attacahed file is maple file.I want to convert this to a pdf file.

conservation_of_wave_eq.mw

## nonlinear differential equation...

hello my friends

I have a critical problem to solve below the system of differential equations

-(9/14)*R(t)^(19/14)-(285/196)*(diff(R(t), t, t))/R(t)^(9/14)+(2565/2744)*(diff(R(t), t))^2/R(t)^(23/14) = -k*(4*lambda+1/a(t)^3)

and R(t) = 6*((diff(a(t), t))^2/a(t)^2+(diff(a(t), `\$`(t, 2)))/a(t))

I need to find form of a(t) numerically from set of differential equatios

plz help me as soon as possible

## ¿How I change the output function to my ODE or PDE...

This is an example, the program gave me functions _F as outputs and i want to see what F is.

This is an example.

Thanks.

## How to use a NULL result from fsolve as a conditio...

Hi, I am using fsolve to find the roots x of a nonpolynomial expression f(x,a) = 0, using a loop for do to vary the values of the parameter a in small identical steps. At some stage, fsolve cannot find a solution. According to the Maple help, in this case fsolve returns a NULL sequence. I would like to know how to use the fact that fsolve cannot find a solution to break the loop with an if-then statement.

## How do I resize a displayed array of 3d plots in M...

Dear all,

In Maple 18, I type the following three lines and I wonder how I can then resize the resulting displayed window:

with(plots):
p1:=plot3d(x*y,x=-1..1,y=-1..1):
display(Array([p1]))

Any idea?

## Newton-Cotes procedure to evaluate coefficients...

Hi all, since I cannot use Latex over here I try to formulate as good as possible. Suppose we have the standard integral from a to b of a function f(x), which is equal to:

h * sum (k=1 to N) [ck f(a+kh)] +O(hp), where h=(b-a)/N+1, an p(N)>= N+1;

Would it be possible to write a procedure to evaluate the coefficients ck , k=1,2,3..N and P(N)

Perhaps a stupid question, because I don't know if it is possible.

Best wishes, Math

## How do i solve first order differential equation w...

Hello,

I am a beginner with Maple. I had some basic tutorials. In fact I want to solve a first order differential equation with non-constant coefficient:

Can you really tell me what are the steps to follow in Maple 18 in order to solve this equation. I didn't find any tutorial or work that deals with variable coefficients.

## Balance of a body with learning sequence with...

Maple 18

Using the learning sequence as an alternative to learn problems related to "balance of a body" is shown in this video; thanks to the kindness that Maple offers us in its fundamental programming syntax.

Balance_of_a_body_with_learning_sequence.mw

Lenin Araujo