## How do I place a variable within a proceduere...

How can I produce the same output with something like alphadeg := alpharad * 180/Pi?

T := proc (p, q, R) alpharad = evalf[5](arccos((1/2)*(p^2+R^2-q^2)/(p*R))), alphadeg = 180*evalf[5](arccos((1/2)*(p^2+R^2-q^2)/(p*R)))/Pi end proc;
T(3, 4, 3.75);

When I try alphadeg = alpharad * 180/Pi I get
Error, illegal use of an object as a name

Thanks! Les    AB59_20170205_Post.mw

## Is there a method to relate groebner bases with mo...

Is there a method to relate groebner bases with monomials ideals

## Is it possible to plot the magnetic field of maxwe...

How to plot magnetic field of maxwell equations like vector field

## How can I use the output of traperror?...

I am debugging a Maple program (and I cannot contact its author). Allegedly, the program ran under some old version of Maple, but it does not run under my Maple 2015 or Maple 9. I am trying to make it run under Maple 2015. I found a place where the program does not do what it is expected to do, but don't know how to make it do what I want:-)

I inserted a DEBUG statement at some place in the program, and the debugger window opens when the program comes to that statement. I execute  the following statement in the debugger:  traperror(Groebner:-NormalForm(g,AA,matermorder)); if I get some benign result, such as 0, I push "continue" in the debugger, and the program runs until it gets to the DEBUG statement again. I repeat these two operations several times until the traperror statement gives the following: polynomials must be members of the algebra" (my comment: only one quotation mark).

So I would like to amend the program to process the exception differently from how it is done now, but I don't know how to get access to the result of the traperror statement. For example, when I am trying to execute the following operators in the debugger: adebug:= traperror(Groebner:-NormalForm(g,AA,matermorder));adebug; , I only get the following diagnostics: Warning, extra characters at end of parsed string  So I don't understand what adebug contains and how I can introduce some logic based on the contents of adebug to handle the exception differently.

I suspect I am missing something simple due to my lack of experience with Maple. I tried to put the result of traperror into a parse statement, but did not get any satisfactory results.

Thank you

## Function that approximates some points better...

I have to calculate a sort of trend line, but I don't know how it works with maple.
I tried with Excel.

Do you think the method is right? How can I replicate it on maple?

```Thanks in advance
```

## Problem for solving system of ODEs...

Dear friends! I am facing problem to solve the below system of ODEs numerically please find the mistake and correct it.

alpha := -1; R := 2; m := 2; Pr := 7; Le := 1.25; Nt := .2; Nb := .2; g := .5; K1 := .1; Q := .5

Eq1 := eta^3*(diff(F(eta), eta, eta, eta, eta))+alpha*(eta^4*(diff(F(eta), eta, eta, eta))+eta^3*(diff(F(eta), eta, eta))-eta^2*F(eta))-2*eta^2*(diff(F(eta), eta, eta, eta))+3*eta*(diff(F(eta), eta, eta))-3*(diff(F(eta), eta))+eta*R*(diff(F(eta), eta))^2-3*eta*R*F(eta)*(diff(F(eta), eta, eta))+3*R*F(eta)*(diff(F(eta), eta))+3*eta^2*R*F(eta)*(diff(F(eta), eta, eta, eta))-eta^2*(diff(F(eta), eta))*(diff(F(eta), eta, eta))-M^2*(eta^3*(diff(F(eta), eta, eta))-eta^2*(diff(F(eta), eta))); Eq2 := eta*(diff(G(eta), eta, eta))+alpha*Pr*eta^2*(diff(G(eta), eta))+R*Pr*F(eta)*(diff(G(eta), eta))+Nb*eta*(diff(G(eta), eta))*(diff(H(eta), eta))+Nt*eta*(diff(G(eta), eta))^2+diff(G(eta), eta)+Q*Pr*eta*G(eta) = 0; Eq3 := eta*(diff(H(eta), eta, eta))+alpha*Le*Pr*eta^2*(diff(H(eta), eta))+R*Le*Pr*F(eta)*(diff(H(eta), eta))+Nt*eta*(diff(G(eta), eta, eta))/Nb+Nt*(diff(G(eta), eta))/Nb+diff(H(eta), eta)-g*Le*Pr*eta*H(eta)-Le*Pr*K1*eta = 0;

IC1 := F(0) = 0, F(1) = 1, (D(F))(0) = 0, (D(F))(1) = 0, (D(G))(0) = 0, G(1) = 1, (D(H))(0) = 0, H(1) = lambda; dsys1 := {Eq1, Eq2, Eq3, IC1}; dsol1 := dsolve(dsys1, numeric, continuation = lambda, range = 0 .. 1);

dsol1x := subs(dsol1, F(eta));

dsol1y := subs(dsol1, G(eta)); dsol1z := subs(dsol1, H(eta));

With my best regards and sincerely.

School of Mathematical Sciences
Peking University, Beijing, China

## How to redirect showstat(....) into a file ?...

Hi everybody,

The sequence
writeto(MyFile)
showstat(Myproc)

keeps printing the result on the screen

How is it possible to redirected the output of showstat(Myproc) into a file ?

## how to convert a nested for loop to iterative vers...

how to convert a nested for loop to iterative version with stack

## how to use assuming x > 0 in if condition statemen...

#my testing for wildcard to one
#after testing, it loop a very long time and not stop
ppp := [[0,0,0,x],[0,0,1,0],[0,1,0,0],[1,0,0,0]]:
check1 := [seq(0,ii=1..nops(ppp))];
ttt1 := [[0,0,0,1],[0,0,1,0],[0,1,0,0],[1,0,0,0]]:
mmmeaght1 := [seq(0,ii=1..nops(ppp[1]))]:
bbb1 := [seq(0,ii=1..nops(ppp[1]))]:
emap := [(xx) -> if [xx < 0 assuming x > 0] then 0 else 1 end if, (xx) -> evalf(1/(1+exp(xx)))]:
#trace(perceptronrule1);
MM(ppp, ttt1, mmmeaght1, bbb1, check1, emap);

when test wildcard variable for input, would like to assume x > 0 then

i try assuming x > 0 , got error

## Intersection between three circles...

I want to calculate the intersection between three circles.
I know that in this case i can calculate intersection of only the first and second equation, but I need this for a interactive component.

The command "intersection"[GEOMETRY] work only with 2 circles.

I did this but it doesn't work.

Thanks.

## Line graphic between two points...

I used the command line betwen two poin, and i saw the graphic.

The line passes for my two point, but i I would like it started in the first point and finished in the second.

Thanks.

## why my Neural network code non-stop running...

when test most simple case one to one, and many to one these two reasonable cases, it run a very long time without exit the program.

when i test with the example in book Neural Network Design, it can output correctly but only for book example.

restart:
with(ExcelTools):
with(ListTools):
with(plots):
with(LinearAlgebra):
zipplus := proc(mm, pp)
return zip((x,y) -> x+y, mm, pp)
end proc:
zipminus := proc(mm, pp)
return zip((x,y) -> x-y, mm, pp)
end proc:
zipstar := proc(mm, pp)
return zip((x,y) -> x*y, mm, pp)
end proc:

metara := proc(pp,meaght,bb,mapp,deep)
if deep > 0 then
pp2 := metara([seq(pp[i], i = 1 .. nops(pp))],meaght,bb,mapp,deep-1):
mp := zip((x,y) -> x*y,pp2,meaght):
mpsam := sum(mp[m],m=1..nops(pp2)):
mpb := [seq(0, i = 1 .. nops(pp2))]:
for ii from 1 to nops(bb) do
mpb[ii] := evalf(mpsam + bb[ii]);
od:
pa := [seq(0, i = 1 .. nops(pp2))]:
for ii from 1 to nops(bb) do
pa[ii] := evalf(mapp[deep](mpb[ii])):
od:
return pa:
else
return pp:
end if:
end proc:

perceptronrule1 := proc(p, t1, meaght1, b1, checksum, mapp)
meaght3 := meaght1:
b3 := b1:
checksum2 := checksum;
print(p[1]):
while sum(checksum2[jj], jj=1..nops(p)) <> nops(p) do
#print("sum(checksum2[jj], jj=1..nops(p))");
#print(sum(checksum2[jj], jj=1..nops(p)));
for ii from 1 to nops(p) do
#print("metara(p[ii],meaght3,b3,mapp,1)");
#print("p[ii]");
#print(p[ii]);
#print("b3");
#print(b3);
#print("meaght3");
#print(meaght3);
#print(metara(p[ii],meaght3,b3,mapp,1));
#print("t1[ii]");
#print(t1[ii]);
e := zipminus(t1[ii], metara(p[ii],meaght3,b3,mapp,1));
#print("e");
#print(e);
meaght2 := meaght3 + zipstar(e,p[ii]);
#print("meaght2");
#print(meaght2);
#print("meaght3");
#print(meaght3);
#print("b3");
#print(b3);
b2 := b3 + e;
#print("b2");
#print(b2);
#print("b3");
#print(b3);
#print("checksum2");
#print(checksum2);
diff1 := zipminus(meaght2, meaght3):
diff2 := zipminus(b2, b3):
if sum(diff1[m],m=1..nops(diff1)) = 0 and sum(diff2[m],m=1..nops(diff2)) = 0 then
checksum2[ii] := 1:
else
checksum2[ii] := 0:
b3 := b2:
meaght3 := meaght2:
end if:
od:
od:
return [meaght3, b3, checksum];
end proc:

#Example from book
ppp := [[2,2],[1,-2],[-2,2],[-1,1]]:
check1 := [seq(0,ii=1..nops(ppp))];
ttt1 := [[0,0],[1,1],[0,0],[1,1]]:
mmmeaght1 := [seq(0,ii=1..nops(ppp[1]))]:
bbb1 := [seq(0,ii=1..nops(ppp[1]))]:
emap := [(x) -> if x < 0 then 0 else 1 end if, (x) -> evalf(1/(1+exp(x)))]:
#trace(perceptronrule1);
perceptronrule1(ppp,ttt1,mmmeaght1,bbb1,check1,emap);

#my testing for one to one
#after testing, it loop a very long time and not stop
ppp := [[0,0,0,1],[0,0,1,0],[0,1,0,0],[1,0,0,0]]:
check1 := [seq(0,ii=1..nops(ppp))];
ttt1 := [[0,0,0,1],[0,0,1,0],[0,1,0,0],[1,0,0,0]]:
mmmeaght1 := [0,0,0,0]:
bbb1 := [0,0,0,0]:
emap := [(x) -> if x < 0 then 0 else 1 end if, (x) -> evalf(1/(1+exp(x)))]:
#trace(perceptronrule1);
perceptronrule1(ppp,ttt1,mmmeaght1,bbb1,check1,emap);

#my testing for many to one
#after testing, it loop a very long time and not stop
ppp := [[1,1,0,0],[0,1,1,0],[0,1,0,1]]:
check1 := [seq(0,ii=1..nops(ppp))];
ttt1 := [[1,0,0,0],[0,1,0,0],[0,0,0,1]]:
mmmeaght1 := [0,0,0,0]:
bbb1 := [0,0,0,0]:
emap := [(x) -> if x < 0 then 0 else 1 end if, (x) -> evalf(1/(1+exp(x)))]:
#trace(perceptronrule1);
perceptronrule1(ppp,ttt1,mmmeaght1,bbb1,check1,emap);

#my testing for one to many
#after testing, it loop a very long time and not stop
ppp := [[1,0,0,0],[0,1,0,0],[0,0,0,1]]:
check1 := [seq(0,ii=1..nops(ppp))];
ttt1 := [[1,1,0,0],[0,1,1,0],[0,1,0,1]]:
mmmeaght1 := [0,0,0,0]:
bbb1 := [0,0,0,0]:
emap := [(x) -> if x < 0 then 0 else 1 end if, (x) -> evalf(1/(1+exp(x)))]:
#trace(perceptronrule1);
perceptronrule1(ppp,ttt1,mmmeaght1,bbb1,check1,emap);

## Representing a circle through [geometry] circle...

Hello,

i need to represent a circle using the command [geometry] circle because i have a problem and i have to calculate an

```intersection between two circles whit command intersection() which is ruled by Package geometry.
```

For example, with the first circle  i did like the help page says

` But it's Error:`

centre of circle(3300;2200)

```I don't understand the eror. Can you help me?
```
```Thanks in advance.

```

## Installation Problem...

Hello.

I've just installed Maple 2015 and when I started it, this happened

It seemed that something was wrong with the graphics or java. But I really don't know what to do next.

## How can I force Maple to be smarter about roots of...

Say I define the following variables.

These are all nineth roots of unity. An equivalent definition would be:

In fact, the following code shows that aa[i] /a[i] =1 for all i, so one would concluse aa[i]=a[i]:

```for i to 9 do
simplify(a[i]/aa[i])
end do```

But when I try to check via "Equal":

I get as output

true
false
false
false
false
false
true
false
false
The problem goes even further since one representation is accepted as a solution of a linear equation system while the other is not.

Another curiosity:

gives just the same expression, whereas simplifying the same expression to the third power gives 0.

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