## Which commands will produce the ODE from the given...

Given the 2 equations below...

-T*sin(theta(t)) = m*(diff(X(t), t, t)+L*(diff(theta(t), t, t))*cos(theta(t))-L*(diff(theta(t), t))^2*sin(theta(t)))

T*cos(theta(t))-m*g = m*(diff(Y(t), t, t)+L*(diff(theta(t), t, t))*sin(theta(t))+L*(diff(theta(t), t))^2*cos(theta(t)))

which command(s) will eliminate T and m to give the ODE below?

L*diff(theta(t), x, x)+(diff(X(t), x, x))*cos(theta)+(diff(Y(t), x, x)+g)*sin(theta) = 0

## How to increase length of legends?...

with ref to the following post

https://www.mapleprimes.com/questions/226211-Subscript-In-Axis-Title-Get-Messed-Up

Now I am having a problem with legends that they are not properly displayed. Dashing of the legends is not displayed in exported graph. Because the legends are too short so they are unable to reflect the dashing of the curves. Is there any way to extend the length? so that the dashing is reflected properly in the legends.

mapleprime.mw

## Why I cannot get simple real expressions for the i...

Hi all,

I have some difficulties to get simple real expressions for those simple integrals with assumptions.

NB: With mathematica, I get simple real expressions results.

Thanks

## Subscript in axis title get messed up while export...

with ref to the following post
https://www.mapleprimes.com/questions/210280-Exporting--Graph-

I am trying to export a plot which contains a subscript in its axis label. The label displays correctly in the maple worksheet but when I export it to a jpg file the subscript gets replaced with square brackets. Kindly guide me how can I get rid of this problem

mprime.mw

## Integrating a function with Runge-Kutta (rkf45), t...

Hey there,

I've been struggling for a few days to integrate a function using rkf45.

For some context, I wish to numerically intergrate a function K * s_R (K,a,w) dK using runge kutta over a 2D grid of (a,w) values. Essentialy, performing the same sort of K-integral many different times for slightly different combinations of a and w. For one such (a,w) combination, the function looks something like this:

and rkf45 works just fine, and returns a numeric result. On the other hand, for a different combination of (a,w), the function looks like this:

and an attempt to perform rkf45 returns the following error: "cannot evaluate the solution past the initial point, problem may be complex, initially singular or improperly set up."

Here is a simplified version of my maple document for reference MaplePrimePleaseHelp.mw.

I'm happy to clarify anything that may be confusing and any thoughts or suggestions would be greatly appreciated.

Thank you!

## Physics question...

I have a physics question I need to program it by Maple , Can you help me to solve ? Its Problem 9.34 from Griffiths

## Using dsolve events to avoid singularities in rung...

Hey there,

I'm trying to numerically intergrate a function s(K,i,j) dK using runge kutta over a 2D grid of i,j values. Essentialy, performing the same sort of integral many different times for slightly different combinations of i and j. The function is more or less gaussian, and so the bulk of the result will come from the values of K around the peak of said gaussian. For some combinations of i and j, the function seems to have a singularity on the right edge of the gaussian peak, which causes my script to spit out an error, telling me the calculation cannot be performed further to the right past the singularity. Now, like i said before, the singularity is on the very edge of the gaussian and therefore I am perfectly happy to stop the integration before the singularity, because anything past it wont contribute very much to the result.

How can I use dsolve events to halt my integration just before hitting the singularity?

`RK := (i, j) -> dsolve({diff(n(K), K) = K*s(K, a[i], b[j]), n(0) = 0}, numeric, method = rkf45)`

## How can the equations of motion include sliding fr...

In the uploaded worksheet a block slides up the Hill from an initial position at an initial horizontal velocity. The block's motion is subject to sliding friction.

How can the equations of the block's motion be obtained to include the effects of gravity and friction?

It may simplify the answer to end the block's upward motion when gravity and friction bring it to an instantaneous halt.

Block_sliding.mw

## How do I solve a system of equations in maple?...

Hi

How can i solve this system of equations:

N and P are variables and the others are constant numbers.

I used "solve" function but the results are:

piecewise(And(1 < c, 1 < d, 1 < k, 0 < -RootOf(exp(_Z)*c*d*k+exp(_Z)*_Z*d-exp(_Z)*c*k-c*d*k+c*k-_Z)*d/((d-1)*c), 0 < -RootOf(exp(_Z)*c*d*k+exp(_Z)*_Z*d-exp(_Z)*c*k-c*d*k+c*k-_Z)), [{N = d*k*(exp(RootOf(exp(_Z)*c*d*k+exp(_Z)*_Z*d-exp(_Z)*c*k-c*d*k+c*k-_Z))-1)/(d*exp(RootOf(exp(_Z)*c*d*k+exp(_Z)*_Z*d-exp(_Z)*c*k-c*d*k+c*k-_Z))-1), p = c*k*(d*exp(RootOf(exp(_Z)*c*d*k+exp(_Z)*_Z*d-exp(_Z)*c*k-c*d*k+c*k-_Z))-d-exp(RootOf(exp(_Z)*c*d*k+exp(_Z)*_Z*d-exp(_Z)*c*k-c*d*k+c*k-_Z))+1)/(d*exp(RootOf(exp(_Z)*c*d*k+exp(_Z)*_Z*d-exp(_Z)*c*k-c*d*k+c*k-_Z))-1)}], [])

## Warning, Run: unable to set assignto result due to...

During running my ws I faced with memory error as below, where as my system have enough memory (120GB)

Warning, Run: unable to set assignto result due to error:  Maple was unable to allocate enough memory to complete this computation.  Please see ?alloc

Maple's help suggests :Software limits are imposed by the -T command-line argument, the datalimit argument to kernelopts and system imposed user limits (for example shell limits).
But I could not understand how to increase software limit.

how to fix that?

## I unprotect the GAMMA, but still receives error, w...

I unprotect the GAMMA, but still receives error:

Error, attempting to assign to `GAMMA` which is protected.  Try declaring `local GAMMA`; see ?protect for details.

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What is the problem?

## How to perform numerical integration with set of v...

Dear all,

Greeting!

I am a new user of Maple. I want to perform a simple (to me, it is very difficult) integration  defined as follows

range from 0 to omega (frequency). alpha^2F (omega) is constant function with set of values (already calculated) for the corresponding frequency. I have calculated the frequencies ranging from 54 to 900 cm-1. Suppose I have alpha^2F(omega)=0, 0.5,0.6,0.7......0.1 for omega=58, 80, 110, 190,.....800, how can I perform this integration  in Maple? Please help me how can I cope with this problem.

Thanks a lot.

Best Regards,

## What is the mathematical description of a velodrom...

I would like to animate the motion of a bicycle racer on a classic velodrome track i.e. one with varied vertical and horizontal curvatures along its length.

Is there a source which explains the math expressions which model the shape of such a track?

## how to pointplot in 3d...

Hi

I have the values of of a function A(x,y,z) in 3d cartesian coordinates as [x[1],y[1],z[1],A(x[1],y[1],z[1])], [x[2],y[2],z[2],A(x[2],y[2],z[2])], [x[i],y[i],z[i],A(x[i],y[i],z[i])],etc...where i vary from 1 to 300 (or higher).

How to plot A(x[i],y[i],z[i]) in 3d.

Thanks