## dummy index summation in maple?...

I did dummy indices implication using add command as below. is it OK or there are mistakes?

Is there another way to imply dummy index summation in maple instead of using add command?

any suggestion???

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 (1.1)

## Can Maple determine the value of DthetaZero such t...

ODE:= -2 sin(1/2 theta(t)) cos(1/2 theta(t)) (diff(theta(t),t)^2-9.8000 sin(theta(t))-(150+4 sin(1/2 theta(t))^2) (diff(theta(t),t,t)=0:

ICS:=  theta(0) = Pi/6, D(theta)(0) = DthetaZero:

## How do I make DocumentTools behave as in the help ...

When I use functions from the DocumentTools to display information in a Maple document, they display a weird bracked along the left hand side of the display. I would like them to display in the same way they do in the help pages. I have attached a document showing the results I get when I repeat some of the examples from the help pages.

display-problems.mw

## DEtools/DEplot/CheckDE) derivatives must be given ...

subs can not make diff(1, t) = 0

sys := simplify(subs(diff(1,t)=0,subs(c(t)=1,[ode1a,ode3a])));
sys := [diff(a(t), t) = 1.342398800*10^5*a(t)+89591*b(t)+44647, 44647*a(t)+44902*b(t)+44859];

DEplot(sys, [a(t), b(t)], t = 0 .. 16, a = -16 .. 16, b = -16 .. 16, color = magnitude, title = `Stable Limit Cycles`, arrows = curve, dirfield = 800, axes = none);
Error, (in DEtools/DEplot/CheckDE) derivatives must be given explicitly

why can not plot?

How do I use characters in a file using the "read" statement?

Example: The following function code is written in a textfile test.mpl.

test:=proc()
print("hüstel");
end proc:

> test()

"h�stel"

The Letter "ü" appears like "�".

If the comand is input direct in the document mode it appears correct:

print("hüstel");

"hüstel"

## unable to evaluate the function to numeric values ...

ygraph1 := -.736312023696564122*exp(2.26140104440167664*10^5*tt)-.591826613918776445*exp(28994.5376895644186*tt)+.328002839648234568*o*exp(13767.7178702679158*tt);
ygraph2 := -.591859486202007235*exp(2.26140104440167664*10^5*tt)+.328381376616263988*exp(28994.5376895644186*tt)-.736116852194203974*o*exp(13767.7178702679158*tt);
ygraph3 := -.327943520064913564*exp(2.26140104440167664*10^5*tt)+.736143281263262450*exp(28994.5376895644186*tt)+.592069351595225779*o*exp(13767.7178702679158*tt);
plot(ygraph1, tt=-5..5);
plot(ygraph2, tt=-5..5);
plot(ygraph3, tt=-5..5);
Warning, unable to evaluate the function to numeric values in the region;

how to plot this system?

## Bug in factors/fsolve...

I have encountered bug in factors/fsolve while working with 19-th degree polynomial:

```restart;

Digits:=150:
T:=-6.22380759047872668130713536877030256364968636070065651396334810246948704517800844289400608484048587112392332204805530128070851889819985512874202683743*10^11*x^15+1.30320674544020861155773378297484119553167774488351680864188235543008368581731239587845304516984389100205019741111280194189829856859808540642557769603*10^10*x^6-4.66269056752439302342961934783764679009596024511170531603537327397832302302620600217387943312388922053304167698527169182278585860427802821480352854136*10^11*x^9-2.23704996926446119043671514798254764988240075983626880645807120500701523185370168392321824617257975062292105400290171941856646211919772527234308968846*10^9*x^5+1.70227750800986164284793608409450414651109713000703213281475661248797845709368255736580952492853671050778821135335145407044800619189451776936359075686*10^12*x^12+2.75132914316444017343930750158891109941047127103886960894939389127711887329536485172215512793127850186551483171384960841607262449527761786758828223621*10^8*x^4-34932.1305741980482332724462824276603543110574918698909627427160477228536038554704823433224807581628905769847550345090785500099182662763447500819501675*x+1.14859089243616386902401277001127426741536679789632050800564282457083136981495352758127041512610195469873039580049988570650313838832989727748112868586*10^12*x^14-6.60479740997269404871863401649844958253760499264982628400515571200965556608668632440745621931354881132921476624343305820884923453724427367494415551238*10^10*x^17-5.62833694496139881587566825658979473046292640751330993837612787833792702707901920475562429114656627532669843830531312111426766840057855202536781521123*10^10*x^7-1.41317084251894030640575308228417182186337397538022537825365672333611503622567981167488384741420461775617951229535582868905095341476313150469092017698*10^12*x^11-8.21268191019727949807038061270674769712976810595535494085869238004490345847174711476348954310804852930678468602300916137608391140935636924900016951244*10^8*x^19+397.252699937115297695173788383107213691513398731729934944369484808586994493337920006396692649274392699364304534062337678482629861430643165733668575822+2.45061767631130714142188028061597642324588736935628490184983950396964320020866945354270367821778753632385377702112725604392839751008695021580743844404*10^11*x^16+1.08699947236093139248842860047684411564605736115175003178583710408973712475471303403438454553797809672473740940054172927497665894877177132800140413775*10^10*x^18+1.84485142971549353599220669614768264648023215439682851036030548807708252959822522849421648368214446092969270608024147362000126035954415744321702508798*10^11*x^8-2.30461084758765666852675422975553976835398815305842562217293737088819307979848024374022174488508670823626363788957243202121075401744096241597591787541*10^7*x^3+9.17691101238967627829517731270700894639677345422963842539705370480050031196020089039807157125184117990094461042715726886282973724309183151499484709563*10^11*x^10-1.59505142070054081045558935086478494555622632474984266672719416019069437321867830698450310020630535513817946854845186492455277659549284062382504657541*10^12*x^13+1.21399269842294123787022397507857250840398420627023248941081275489711499859955449395398103964932227544163416388726749227644470585060488880538430515276*10^6*x^2:

infolevel[fsolve]:=3:
fsolve(T,fulldigits); # <-- completes without issues

factors(T);           # <-- freezes with log:
fsolve: ill-conditioned polynom of degree 19, with 0(0) given roots
fsolve: 1th root found in 9 iters at 165 Digits
fsolve: 2th root found in 11 iters at 164 Digits
fsolve: 3th root found in 11 iters at 165 Digits
fsolve: 4th root found in 10 iters at 174 Digits
fsolve: 5th root found in 10 iters at 167 Digits
fsolve: 6th root found in 11 iters at 168 Digits
fsolve: 7th root found in 11 iters at 174 Digits
fsolve: 8th root found in 11 iters at 170 Digits
fsolve: 9th root found in 11 iters at 181 Digits
fsolve: 10th root found in 11 iters at 172 Digits
fsolve: 11th root found in 12 iters at 175 Digits
fsolve: 12th root found in 11 iters at 182 Digits
fsolve: 14th root found in 14 iters at 177 Digits
fsolve: 15th root found in 10 iters at 176 Digits
fsolve: 16th root found in 11 iters at 173 Digits
Warning,  computation interrupted

```

The most interesting thing is that standalone 'fsolve' finishes fine, but 'factors' freezes in 'fsolve:-polyill' on the same polynomial.

My system is: Windows 7 x64, Maple 2017.0.

Would appreciate any help on how to avoid the issue with 'factors'.

## invalid input: PDEtools/NumerDenom...

ode1a := diff(a(t), t) = 1.342398800*10^5*a(t)+round(89591.20000)*b(t)+round(44647.44000)*c(t);
ode2a := diff(b(t), t) = round(89591.20000)*a(t)+round(89803.24000)*b(t)+round(44901.60000)*c(t);
ode3a := diff(c(t), t) = round(44647.44000)*a(t)+round(44901.60000)*b(t)+round(44859.24000)*c(t);
sol := dsolve([ode1a=exp(t), ode2a=exp(t), ode3a=exp(t)], [a(t),b(t),c(t)]);

Error, (in dsolve) invalid input: `PDEtools/NumerDenom` expects its 1st argument, ee, to be of type algebraic, but received diff(a(t), t) = (3355997/25)*a(t)+89591*b(t)+44647*c(t)

initially i guess the error come from decimal number coefficient

but after round it, still have error

## how to apply ricci flow?...

ode1a := diff(y1(tt), tt) = 1.342398800*10^5*y1(tt)+89591.20000*y2(tt)+44647.44000*y3(tt);
ode2a := diff(y2(tt), tt) = 89591.20000*y1(tt)+89803.24000*y2(tt)+44901.60000*y3(tt);
ode3a := diff(y3(tt), tt) = 44647.44000*y1(tt)+44901.60000*y2(tt)+44859.24000*y3(tt);

would like to find the origin eigenstate before it collapse to eigenvalues

how to apply ricci flow in this situation?

i find help file , and can not find some relationship between this application and inputs of ricci related function

which functions in maple can help to find origin of eigenstate

## how to deplot this case?...

ode1a := diff(y1(tt), tt) = 1.342398800*10^5*y1(tt)+89591.20000*y2(tt)+44647.44000*y3(tt);
ode2a := diff(y2(tt), tt) = 89591.20000*y1(tt)+89803.24000*y2(tt)+44901.60000*y3(tt);
ode3a := diff(y3(tt), tt) = 44647.44000*y1(tt)+44901.60000*y2(tt)+44859.24000*y3(tt);

DEplot3d({ode1a,ode2a,ode3a}, {y1(tt), y2(tt), y3(tt)}, tt=0..10,[[y1(0) = 0, y2(0) = 0, y3(0) = 0]],scene=[tt,y1(tt),y2(tt)]);
DEplot3d({ode1a,ode2a,ode3a}, {y1(tt), y2(tt), y3(tt)}, tt=0..10,[[y1(0) = 0, y2(0) = 0, y3(0) = 0]],scene=[tt,y1(tt),y3(tt)]);
DEplot3d({ode1a,ode2a,ode3a}, {y1(tt), y2(tt), y3(tt)}, tt=0..10,[[y1(0) = 0, y2(0) = 0, y3(0) = 0]],scene=[tt,y2(tt),y3(tt)]);

can it plot 3 functions ?
and why it return a straight line 3d graph

is there some interesting graph from this system?

## apply while loop inside other while loop...

iam trying to apply newton method on non liner system but i have a problem for apply while loop inside other while loop

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## implicit Scheme(Crank-Nicolson method)...

hey... can u help me how to solve my problem using the Implicit Crank Nicolson Finite different Method. 1_ques_crank.mw..... problem in variable name A and u .. how to solve this

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## mod function help needed...

please see attachment and explain why the output of the 2nd line is not 0

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## Error, (in plot) unexpected options...

Dear all,

I'm trying to plot dispersion curves in Maple but I'm having some trouble. The code is attached as a file also.

f1  is my main function and I want to plot Vx with regard to f as all the rest are known variables, but I'm not able to do so.

I hope that someone can tell me why do I have this error.

restart;
f1 := (C33*Rp*kzp+C13*kx)*(Rm*kx+kzm)*sin(kzp*h)*cos(kzm*h)-(C33*Rm*kzm-C13*kx)*(Rp*kx+kzp)*sin(kzm*h)*cos(kzp*h)=0;
Rp := (-C11*kx^2-C55*kzp^2+omega^2*rho)/((C55+C13)*kx*kzp);
Rm := (-C11*kx^2-C55*kzm^2+omega^2*rho)/((C55+C13)*kx*kzm);
kzp := sqrt(((-M+sqrt(M^2-4*N))*(1/2))*kx^2);
kzm := sqrt(((-M-sqrt(M^2-4*N))*(1/2))*kx^2);
M := (C11*C33/rho^2-2*C55*C13/rho^2+C13^2-omega^2*(C33+C55)/(rho*kx^2))*rho^2/(C33*C55);
N := (omega^2/kx^2-C11/rho)*(omega^2/kx^2-C55/rho)*rho^2/(C33*C55);
C11 := 0.435e10;
C13 := 0.259e10;
C55 := 0.112e10;
C33 := 0.108e11;
rho := 923;
h := 0.7e-2*(1/2);
kx := omega/Vx;
omega := 2*Pi*f;
f1;
plot(f1, f = 10 .. 0.100e6);
Error, (in plot) unexpected options: [(.4633081900*(-0.1717311166e12*f^2/Vx^2-0.2210791386e11*(...

Asim_dispers.mw