## How to refer to previous result?...

I want to reference the previous equation/expression which is not displayed (':')in my worksheet. I allready know the '%' sign, but this references the previous equation/expression which was executed . By previous I mean the result (which is not displayed) in the previous line.

As I do not want the previous equation to be displayed I also cannot use the equation lable (CTRL+L).

Example

x:=a=b+1:

solve(previous,{b});

## Maple doesn't recognize 'complexplot3d'...

I'm new here, so I'm not totally sure this is the right place to ask this. I apologize if it isn't, please let me know in that case.

My problem is that Maple won't recognize the built-in command 'complexplot3d'. For example, typing:

complexplot3d(z^2, z = -1-I .. 1+I)

doesn't do anything, and it's displayed again in blue as if it was not a command.

Any kind of help would be extremely helpful, as I have no clue of what's going on. Thanks in advance!

## How to solve BVP by shooting method?...

Hi everyone,

I'm kinda new here, and I really hope you guys can help me through this. In my new case study, after some revision, i thought i might be trying to implement a shooting method. I tried my best to make it work/understand but i couldn't get to any result.

So, as attached (i re-do PV Satya Naraya's paper first to be more understand but .....)

Here is my questions and the worksheet:

1) really stuck in mind - what is the purpose of shooting method for some related study?

2) what is the meaning of error .............'use midpoint method intead"

3) Worksheet - 1MASS_JEFF_SATYA_on_Beta.mw

Thanks in advanced. Really hope that someone can help/teach me how to solve the boundary value problem by shooting method.

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## How to add a legend to a plot?...

Good morning everybody

I know this question has already been widely discussed, for example in
http://www.mapleprimes.com/questions/149585-How-To-Order-Legend-Of-Multiple-Plots

I used the answer Kitonum then gave because I have basically the same kind of problem.
As an illustration, here is a sketch of my coding :

N := 3:
for k from 1 to N do
...
MyPlot||k := PLOT(CURVES(....)):
...
end do:
plots:-display(seq(MyPlot||k, k=1..N));

The only difference is that I use PLOT instead of plot ... so I have thought that using LEGEND instead of legend would give me the desired result.
But I don't understand how to use LEGEND and how to place the legend in the correct location.

## How to find root for equation with 'w'?...

Here, I attached my maple code. I need to find root. I am using fsolve. But I am not geting the root. Please any one help me... to find the root.

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## Fibonacci sequence...

Hello

Any idea about the summation of Fibonacci sequence

Fibonacci.mw

Best regards

## Forcing Branch Choice with the LambertW...

Is there a way to force the branch choice with the LambertW?

If I turn on all _EnvAllSolutions:=true:

I get a placeholder for the branch. Unfortunately the name of this placeholder changes every time I re-evaluate.

Is there a way to force this to take a certain value?

Regards.

## Problem with dsolve...

Hello, My problem is as following:

I have tried 2 options for solving the problem below, trying to plot the behaviour of a system to a predetermined function.

First I tried to use dsolve as usual:

restart; with(plots); C := setcolors(); with(LinearAlgebra);
eq1 := Force = Mass*(diff(y(t), `\$`(t, 2)));
formula1 := 2.6*BodyWeight*abs(sin(4*Pi*t));
2.6 BodyWeight |sin(4 Pi t)|
BodyWeight := 80*9.81;
plot(formula1, t = 0 .. 2);

eq2 := formula1-SpringConstant*(diff(y(t), t)) = Mass*(diff(y(t), `\$`(t, 2)));
/ d \ / d /
2040.480 |sin(4 Pi t)| - SpringConstant |--- y(t)| = Mass |--- |
\ dt / \ dt \

d \\
--- y(t)||
dt //
Mass := .200;
Springt := 200;
200
SpringConstant := Youngsmodulus*Surface/DeltaLength;
DeltaLength := 0.2e-1-y(t);
Surface := .15;
Youngsmodulus := 1600*10^6-20*t^2;
eq2;
/ 2 \ / d \
0.15 \-20 t + 1600000000/ |--- y(t)|
\ dt /
2040.480 |sin(4 Pi t)| - ------------------------------------- =
0.02 - y(t)

/ d / d \\
0.200 |--- |--- y(t)||
\ dt \ dt //

incs := y(0) = 0, (D(y))(0) = 0;
eq4 := dsolve({eq2, incs});
Warning: System is inconsistent

Second, I tried using a numerical solving, with maxfun.

restart; with(plots); C := setcolors(); with(LinearAlgebra);
eq1 := Force = Mass*(diff(y(t), `\$`(t, 2)));
formula1 := 2.6*BodyWeight*abs(sin(4*Pi*t));
2.6 BodyWeight |sin(4 Pi t)|
BodyWeight := 80*9.81;
plot(formula1, t = 0 .. 2);

eq2 := formula1-SpringConstant*(diff(y(t), t)) = Mass*(diff(y(t), `\$`(t, 2)));
/ d \ / d /
2040.480 |sin(4 Pi t)| - SpringConstant |--- y(t)| = Mass |--- |
\ dt / \ dt \

d \\
--- y(t)||
dt //
Mass := .200;
Springt := 200;
200
SpringConstant := Youngsmodulus*Surface/DeltaLength;
DeltaLength := 0.2e-1-y(t);
Surface := .15;
Youngsmodulus := 1600*10^6-20*t^2;
eq2;
/ 2 \ / d \
0.15 \-20 t + 1600000000/ |--- y(t)|
\ dt /
2040.480 |sin(4 Pi t)| - ------------------------------------- =
0.02 - y(t)

/ d / d \\
0.200 |--- |--- y(t)||
\ dt \ dt //

incs := y(0) = 0, (D(y))(0) = 0;
eq4 := dsolve({eq2, incs}, y(t), type = numeric, output = listprocedure, maxfun = 10^7);
[
[t = proc(t) ... end;, y(t) = proc(t) ... end;,
[

d ]
--- y(t) = proc(t) ... end;]
dt ]

test := rhs(eq4[2]);
proc(t) ... end;

This one does plot, but no further than 0.2*10^-6. I have tried compiling the data, but this has not worked yet.

Does anyone know a way to work around such a problem. Is it possible to plot the equation using a for loop? If yes, how?

## How to pull propane prices from website...

How do I use Maple to pull the propane price from www.fuelsonline.ca ?

If I use HTTP[Get]("http://www.fuelsonline.ca")

I only get            301,""

Any help?

## In seq function "division by zero"...

Hello everybody.

I have a function:

f(x,y)=GAMMA(y, -ln(x))/GAMMA(y)

seq(sum(f(x, y), y = 0 .. 1), x = 0 .. 5)

and I got a error message:

Error, (in ln) numeric exception: division by zero ??
This is normal behavior in seq function or Bug?

but  when I'm first calculate the sum sol := sum(f(x, y), y = 0 .. 1) -> x,

and evalf([seq(sol, x = 0 .. 5)]) ->[0., 1., 2., 3., 4., 5.] works fine.

Seq-division_by_zero.mw

Mariusz Iwaniuk

My old harddisk recently died and I am currently using a new one. I still have the license code for Maple 2016. Is it still possible for me to install Maple 2016 or 1 license = 1 installation?

## Numerical solution of integral equation...

hi,

how we can use maple to find solution of singuler integral equation by using product nystrom method or toeplitz method in maple?

## Syntax of Legend...

Hi everyone,

I am pretty new in MAPLE and I am having trouble doing a really easy thing.

I would like to do a plot and add a legend.

I know how to do a plot and I succeeded but I don't know how to write the legend. I want a legend that looks like:

I have stored in my K__V the value 0.2. How can I do that?

I tried with legend = 'K__V'

This is ok to write the first part, but then how do I write the second one: ' = 0.2 ' ?

Of course I don't want to write 0.2 directly but I want to write K__V in this way the legend will change according to the value of K__V.

In MATLAB what I want to write is really easy to do:
legend('K__V=%d',K__V)

I hope I was clear.

Thanks

## The abs function in Excel...

Hello,

I have an array/vector of values as results of a function:

=maple("Fm:=x->(Qv(x)+&1*Qm(x))/2";B3)

=maple("G:=map(g->evalf(eval(Fm(x),x=g)),[A])")

Now I need the maximum of absolute values of G!!

=maple("max(G)") I have maximum, but I want =maple("max(abs(G))") But there is an error in this expression!!

## Interaction between two packages...

Hello everybody,

* The following set of instructions returns me an error

restart:
with(Maplets[Examples]):
A := Matrix(2,2,[1,2,3,4]):
LinearAlgebra:-Transpose(A);

Error, Transpose is not a command in the Maplets:-Examples:-LinearAlgebra package

(it would be the same for any other command from the LinearAlgebra package)

* If I try

restart:
with(Maplets[Examples]):
with(LinearAlgebra):
A := Matrix(2,2,[1,2,3,4]):
Transpose(A);

the answer is Transpose(...),  as if Transpose was an undefined function (no matter the order of the loading of the two packages)

* In Maplets[Examples] there is a subpackage named LinearAlgebra : could it be the reason of these observed behaviour ?
* Is there any way to fix that other than copying from Maplets[Examples] the only pieces of code I need avoiding thus its complete loading ?
* More generally : is it possible to load a package "partly" by discarding some of its subpackages ?