## Problem with finite sum. Negative upper limit...

Hi Dears,

I'm have a code like this:

sum(-GAMMA(k+1, x), k = 0 .. -2) and Maple give me : Ei(1, x).

How to check that answer is correct?

I am looking forward to hearing from you.

## Why do these VectorCalculus TNB commands give inco...

For the space curve in the linked worksheet, RadiusOfCurvature and Binormal give incorrect results. Why?

TNB_anomalies.mw

## Maple in the teaching of Mathematics for Civil...

Maple 2016

In the present work it has been shown how Maple helps in the teaching of Mathematics in the different subjects that it has. Using a Maple worksheet as if it were a class preparation notebook could develop problems such as: Vector Analysis, EDO, EDP, Statistics, Algebra, Geometry, etc., among others; Taking as a method of solution the clickable-mathpopup, the right click (contextual) or at best embedded components. No criteria or prerequisite is needed to use Maple; Rather than being willing to forget the traditional slate and down and replace it with dynamic leaves that maple offers us; To achieve excellent academic profiles both individually and in groups. The proprietary methods are used to develop applications (math-apps) being a professional criterion; That is to say, according to the problematic reality, we are looking for enduring interactive solutions. Here we use the graphical algorithm and the block diagram as a solution proposal but not as something obligatory to implement solutions. We take as a teaching-learning measure the results of our students in the ability to analyze and interpret the results; Since in the times of calculation; Maple helps tremendously; Opening up this way to train students competent in basic sciences and engineering.

II_SEMINARIO_UNT_2017.pdf

In Spanish

Lenin Araujo Castillo

## command to retrieve a solution...

Hi

I have a set of differential equations which I have solved for a specific value, and would like to use the second answer (F__A(V)) in my next calculations

What command can I use to retrieve that value?

sol(0.1e-4);
[V = 0.00001, F__A(V) = HFloat(3.498873118476744e-6),

F__B(V) = HFloat(1.9101126881523255e-5),

F__C(V) = HFloat(9.550563440761627e-6)]

Regards

## a problem with integral command (evalf(Int))...

when i use the command evalf(Int(f(y),y=-b..b)), i expect that the output of this command to be an integer. but the output is to form of below:

i think that the problem is because of the form of the function f(y) that is the form of below:

f(y) = a*10^354*(b*10^-356*g(sin(y) , cos(y) and exp(y)))

but i dont know how i solve this problem:(

## Animations not displaying...

I am experimenting with rotating a group of pionts, lines cylinders etc. the only aminations that  will display are where I put the transformations directly as the point coordinates. This is very tedious. Is there a way around this problem efficiently? Attached worksheet shows problem(s). Ultimately I will have a whole group of objects to rotate.

 (1)

 (2)

 (3)

 (4)

 (5)

 (6)

 (7)

 (8)

 (9)

 (10)

 (11)

 (1)

 (2)

 (3)

 (4)

 (5)

 (6)

 (7)

 (8)

 (9)

 (10)

 (11)

## maple2016 will not start in a linux x2go session, ...

Connecting to a linux x2go server with an x2go client (tried Mac and Linux) and try to start maple2016 in a terminal, I get this error:

\$ /opt/maple2016/bin/xmaple
Picked up JAVA_TOOL_OPTIONS:
Exception in thread "Request id 1" java.lang.UnsupportedOperationException: PERPIXEL_TRANSLUCENT translucency is not supported
at java.awt.Window.setBackground(Window.java:3842)
at java.awt.Frame.setBackground(Frame.java:988)
at com.maplesoft.worksheet.application.WmiSplashScreen.<init>(Unknown Source)
at com.maplesoft.worksheet.application.WmiGenericStartupStrategy.showSplash(Unknown Source)
at com.maplesoft.worksheet.application.WmiGenericStartupStrategy.doStartup(Unknown Source)
at com.maplesoft.worksheet.application.WmiWorksheetStartupStrategy.doStartup(Unknown Source)
at com.maplesoft.application.Maple.doStartup(Unknown Source)
at com.maplesoft.application.Application.startup(Unknown Source)
at com.maplesoft.application.ServerProtocol\$StartApplicationHandler.processCommand(Unknown Source)
at com.maplesoft.application.ServerProtocol.executeCommand(Unknown Source)
at com.maplesoft.application.ServerProtocol.processNextStep(Unknown Source)
at com.maplesoft.application.ExchangeProtocol.executeProtocol(Unknown Source)
at com.maplesoft.application.ApplicationManager\$Listener.run(Unknown Source)

The same xmaple will start graphically if I connect with a normal remote X connection. However a normal remote X connection is unusable on a slow network connection.

## Maple 2016 won't launch...

Hello,

Maple 2016 used to work fine on my PC but now it won't even load. Whenever I try to click the program I can see the loading icon next to the cursor and then nothing happens next. It works fine on my laptop and I'm using the program under a univsersity license. Yesterday I was able to open it once for some reason and now it's the same as before. I've tried uninstalling it again and again several time but that doesn't work.

Any help would be much appreaciated.

## "If" not passing through...

Hello!

I was creating this code for the "Müller Method" for Numerical Analysis. Everything works fine till the if (for getting the x3) goes on. The problem is, the Maple doesn't detects the if.
I tried checking every variable and every variable is calculated except "x3"; even "disc".

I would like to know what happened. Anyways, here's the code:
http://imgur.com/a/DGlgl

```
x0 := 0; x1 := 8.4; x2 := 10; iter := 1000; tol := 10^(-8); f := proc (x) options operator, arrow; 3*x^3+7*x^2+x+2 end proc; f(x); plot(f(x), color = green); printf(" n          x0               x1               x2              x3                Error \n"); for i to iter do d0 := evalf((f(x1)-f(x0))/(x1-x0)); d1 := evalf((f(x2)-f(x1))/(x2-x1)); h1 := evalf(x2-x1); h0 := evalf(x1-x0); a := evalf((d1-d0)/(h1-h0)); b := evalf(a*h1+d1); c := evalf(f(x2)); disc := sqrt(-4*a*c+b^2); if abs(b+disc) > abs(b-disc) then x3 := x2+(-2*c)*(1/(b+sqrt(-4*a*c+b^2))); erry := abs((x3-x2)/x3) else x3 := x2+(-2*c)*(1/(b-sqrt(-4*a*c+b^2))); erry := abs((x3-x2)/x3) end if; if erry > tol then x0 := x1; x1 := x2; x2 := x3; printf("%2d     %2.8f      %2.8f       %2.8f         %2.5 f     %2.8 f \n", i, a, b, c, x3, erry) else printf("una raiz es: %2.8f ", x3); break end if end do;
```

I put the image (as it looks on my maple) and the "code" so you can copy-paste it in Maple.

## LSSolve on a large ODE system...

hello i have the following set of ode's:

ode_sub := diff(S(t), t) = -k1*S(t)-S(t)/T1_s;
ode_P1 := diff(P1(t), t) = k1*S(t)-k2*(P1(t)-P2(t)/keq)-P1(t)/T1_p1;
ode_P2 := diff(P2(t), t) = -k2*(-keq*P1(t)+P2(t))/keq-k4*P2(t)-P2(t)/T1_p2;
ode_P2e := diff(P2_e(t), t) = k4*P2(t)-P2_e(t)/T1_p2_e;

ode_system := ode_sub, ode_P1, ode_P2, ode_P2e;

with these parameters:
s0 := 10000;
k2 := 1000; T1_s := 14; T1_p2_e := 35; T1_p2 := T1_p1;

i want to find the unkown parameters : T1_p1, k1, keq and k4

init:=S(0)=s0,P1(0)=0,P2(0)=0,P2_e(0)=0

dsolve({ode_system,init})

sol := combine(expand(%));
PS := subs(sol, [S(t), P1(t), P2(t), P2_e(t)]);

P1fu := unapply(PS[2],t);
Sfu := unapply(PS[1],t);
P2fu := unapply(PS[3],t);
P2e_fu := unapply(PS[4],t);
P2_total := unapply(P2fu+P2e_fu, t);

the following data is given:

T:=<0,2,4,6,8>

S:=<9999.99913146527,8328.870587730016,6937.009129218748,5777.745632133724,4812.209983843559>

P1:=<0.0,67.86790056712294,114.88787098501874,145.95438088662502,164.85650644237887>

P2_P2e:=<0.0,271.68492651947497,461.9130396605823,589.3710176125417,668.9967533337124> # data from P2(t)+P2_e(t)

making the rediduals:

RP1 := convert(P1-P1fu~(T), list);
RS := convert(S-Sfu~(T), list);
RP2_P2e := convert(P2_P2_e-P2_total~(T), list);

RPs := [op(RS), op(RP2_P2_e), op(RP1)]

res := Optimization:-LSSolve(RPs, k1 = 0 .. 1, keq = 0 .. 10, k4 = 0 .. 1, T1_p1 = 0 .. 100)

i dont know wheter or not the last step work to get the parameters becuase it takes to long to compute. is there a smarter way to obtain the parameters of the ode's? a numeric approch ?

i tried with dsolve({ode_sysytem,init},numeric,'parameters'=[k1,keq,k4,T1_p1]) however it doesnt seem to get my anywhere since i need to know the parameters to use this (i think)

hope someone can help:)

## Happy Valentine's Day

by: Maple 2016

In the creation of this animation the technique from here  was used.

The code of this animation:

with(plots): with(plottools):
SmallHeart:=plot([1/20*sin(t)^3, 1/20*(13*cos(t)/16-5*cos(2*t)/16-2*cos(3*t)/16-cos(4*t)/16), t = 0 .. 2*Pi], color = "Red", thickness=3, filled):
F:=t->[sin(t)^3, 13*cos(t)/16-5*cos(2*t)/16-2*cos(3*t)/16-cos(4*t)/16]:
Gf:=display(translate(SmallHeart, 0,0.37)):
Gl:=display(translate(SmallHeart, 0,-1)):
G:=t->display(translate(SmallHeart, F(t)[])):
A:=display(seq(display(op([Gf,seq(G(-Pi/20*t), t=3..k),seq(G(Pi/20*t), t=3..k)]))\$4,k=2..17),display(op([Gf,seq(G(-Pi/20*t), t=3..17),seq(G(Pi/20*t), t=3..17),Gl]))\$30, insequence=true, size=[600,600]):
B:=animate(textplot,[[-0.6,0.25, "Happy"[1..round(n)]],color="Orange", font=[times,bolditalic,40], align=right],n=0..5,frames=18, paraminfo=false):
C:=animate(textplot,[[-0.2,0, "Valentine's"[1..round(n)]],color=green, font=[times,bolditalic,40], align=right],n=1..11,frames=35, paraminfo=false):
E:=animate(textplot,[[-0.3,-0.25, "Day!"[1..round(n)]],color="Blue", font=[times,bolditalic,40], align=right],n=1..4,frames=41, paraminfo=false):
T:=display([B, display(op([1,-1,1],B),C), display(op([1,-1,1],B),op([1,-1,1],C),E)], insequence=true):
K:=display(A, T, axes=none):
K;

The last frame of this animation:

display(op([1,-1],K), size=[600,600], axes=none);  # The last frame

Edit. The code was edited - the number of frames has been increased.

## Bug in Optimization

Maple 2016

Let us consider the linear integer programming problem:

```A := Matrix([[1, 7, 1, 3], [1, 6, 4, 6], [17, 1, 5, 1], [1, 6, 10, 4]]):
n := 4; z := add(add(A[i, j]*x[i, j], j = 1 .. n), i = 1 .. n):
restr := {seq(add(x[i, j], i = 1 .. n) = 1, j = 1 .. n), seq(add(x[i, j], j = 1 .. n) = 1, i = 1 .. n)}:
sol := Optimization[LPSolve](z, restr, assume = binary);

Error, (in Optimization:-LPSolve) no feasible integer point found;
use feasibilitytolerance option to adjust tolerance

sol1 := Optimization[LPSolve](z, restr, assume = binary, feasibilitytolerance = 100, integertolerance = 1);

Error, (in Optimization:-LPSolve) no feasible integer point found;
use feasibilitytolerance option to adjust tolerance
```

That was OK in Maple 16, outputting

.

The bug in one of the principal Maple commands lasts since Maple 2015, where the above code causes "Kernel connection has been lost". The SCRs about it were submitted three times (see http://www.mapleprimes.com/questions/204750-Bug-In-LPSolve-In-Maple-20151).

## Maple 2016 exited with code 158...

This is simplified from a larger example.  I never saw Maple exit from a numercal calculation.

> 123456789 ^ 987654321:
Execution stopped: Stack limit reached.

Process Maple R2016 exited abnormally with code 158

> kernelopts(maxdigits);
38654705646

> lprint(123456789. ^ 987654321.);
.4339566080e7991619731

kernelopts(memusage) shows about 2~3 meg bytes used.

The system has 16G Ram.  16G swap.

Seems like something maple should have caught.

## One simple differential equation...

Try solve

restart; with(PDEtools);
U := diff_table(u(x, y, z));

pde[1] := x*y*U[z]+x*U[x]+2*y*U[y] = 0;

bc[1] := eval(U[], z = 0) = x^2+y^2;
sys[1] := [pde[1], bc[1]];
pdsolve(sys[1])

Maple nothing returned. Where my mistake ?? Thank you.