## How to return a correct Boolean value?...

To my knowledge, I think it should return 'true'. But in this case and many other similar cases, it returns 'false'. Sometimes after rebooting my laptop it gives 'true'. This made me crazy. Please help!

## Difference between 'map' and '~(element-wise opera...

Hello there,

Would you allow me to ask this one question?

What is the difference between 'map' and '~(element-wise operation)'?

The following worksheet snipped shows an example:

Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/Q20210612.mw .

I thought that both operations were the same, but seemingly they are not.

Best Regards,

In Kwon Park

## Can we change the usual range way of an animation...

Suppose that we have something like

plots:-animate(F,[theta],theta=0..2*Pi,background=plot([cos(t)-2,sin(t),t=0..2*Pi]),
scaling=constrained,axes=none);

I want to change the range of the parameter theta to something like theta=L[i],i=1..20.
Here, L is a list of numbers. Can I?
Thank you.

mapleatha

## Extract specific items of expression....

I 'd like to extract all items that contain "a" in an expression except "ab". What I can think of is to use the two functions select and remove to do it, but I feel a little less automated. Is there a better way?

f := a*b+a*c+a+b+c
s:=remove(has,select(has,[op(f)],a),a*b)

s := [a c, a]

## Problem with maple ...

Hello, I have a program which works fine in maple but get stuck when I use it in maple 2021 please I need your help thank you in advance

mpprime.mw

Hi all,

This is my first time working on a problem using Maple, and I've run into some issues regarding plotting my findings. After putting in the information for the plot (p:= plot([y1], t = 0..56562.16837, y = 0.10]), I keep receiving the warning "Expecting only range variable t in expression y[1] to be plotted but found name y[1]. I attached the Maple worksheet below for more information, trying to work my way through plotting in Maple.

Worksheet.mw

## Why is the minus sign so weak even in the bold fon...

Why is the minus sign so weak even in the bold font case? My students sometimes miss it in online tests.
How do we make the minus sign bolder?
Thank you!

mapleatha

## Sum every fifth term in an expression...

Hi... I have a long-expression, which I have abbreviated here. I want every 5th term summed. Included is my code, but I need the unassign command (after point 12) for it to work. The problem is when I unhash and insert this unassign('s','X[4]') command into my actual Table of Records procedure, Maple protests. it gives a cryptic: " Error, `(` unexpected " .
How can I modify the original code to sum every 5th term as efficiently as possible as the thing is a 4000 term expression which I later need to numerically integrate?

sum_every_5th.mw

## Round decimal up or down...

Hey

Does Maple have the equivalent of the MROUND Excel command?

Or can someone kindly make a procedure.

eg

MROUND(1986,10)=1990

MROUND(492,5)=490

thanks!

## Strange Optimization Output...

Hello everyone

I observe the following "strange" case and I am wondering if I am missing something. So, any insights are more than appreciated. The case is the followin:

When I use

with(Optimization):
Interactive(x + y, {x = 0 .. 1, y = 0 .. 1, 1 <= x + y})

I get: objective =1, x=y=.5

However, If I run

with(Optimization):
Minimize(x + y, {x >=0,x<=1, y>=0,y<=1, 1 <= x + y})

then I get: objective =1, x=1, y=0

Why there is such a difference? Because of there are multiple solutions?

## How to Plot a Colored Surface Under plot3d That Is...

Hi MaplePrimes team,

I want to create two 3d surfaces with plot3d command in Maple, one of which represents a light-emitting diode (LED).

For that, my idea is simple: Just to disable the shade on a specific surface (representing the LED-like) among other surface. So, whatever the direction of the light, the LED surface keeps a constant luminosity.

Unfortunately, the glossiness = 0 option is still dependent of light direction.

I looked at all the options for plot3d and display commands, but I couldn't find anything for disable light on special surface.

Maybe in PLOT3D command?

If not, is there an option to add a second light source?

Simple example I would like create:

- 1. A surface with regular light:

BALL := plot3d(<cos(t)*cos(s), cos(t)*sin(s), sin(t)>, s = 0..2*Pi, t =-Pi/2..Pi/2, color = "Blue"):

- 2. An illuminated surface representing the LED:

LED := plot3d((<2 + cos(t)*cos(s), cos(t)*sin(s), sin(t)>, s = 0..2*Pi, t =-Pi/2..Pi/2, color = "Yellow", What option to insert?):

Then, the assembly will give:

display(BALL, LED);

My Advanced Applications Tests in Maple

Figure 1: Aisle LED light and LED-screens of first-class seats in an illuminated cabin on board of an aircraft.

Figure 2: Here is the problem in the darkness. The aisle LED light and LED-screen must be stay constantly illuminated for any direction of light.

To better understand my objectives, here is another image using lights. Note that the LEDs (pale yellow strip shapes) stay constantly illuminated whatever the daylight and therefore allowing the aircraft to be visible.

Figure 3: Exterior lighting systems and dazzling jet engine afterburner of a military transport aircraft concept.

Best.

Guy.

## How do I print (3*Pi)/10 instead of Maple's (3/10)...

I need to get more tickmarks in my plots by reducing the size of fractions produced by Maple.
For example, instead of (3*Pi)/10, Maple gives me (3/10)*Pi. Any help would be appreciated.
I can actually convert all there Maple numbers to fractions, but Maple will not accept these conversions as tickmarks.
Thank you.
mapleatha

## How do I output sin(x) in red in this title?...

I need tto change the color of a word or a math expression inside the title of a Maple plot.
For example, I need to have sin(x) in red in this axes plot:

AX:=plot([[x,0,x=0..Pi],[0,y,y=0..1]],color=black,thickness=3,title=typeset("\nLeft Riemann Sum for the Function:\n",sin(x), "on the interval ", [0,Pi]\n),titlefont=["Arial",25]):

How do I do it?

Thank you!

mapleatha

## Setup Differential Equation into a Matrixform...

I'm practicing with matrices in Maple, but I have a question. My question is, how do I set up the differential equation system on matrix form x '(t) = Ax (t) + B?

Here are the equations:

x'1(t) = x1(t) - x2(t) - 3

x'2(t) = 12x1(t) - 8x2(t) + 4

I've been looking around for some help sources, but the only one I could find is this. I tried to set it up like that, but didn't work, it gave me an error.

How should I set it up (using Maple commands)?