Given an expression, how to best find the constants _C1, _C2, etc.... in this expression?  Currently I do the following, but I think there should be a better way.

restart;
sol:=dsolve(diff(y(x),x$2)+y(x)=1);
indets(sol);
select(x->`if`(type(x,symbol) and convert(x,string)[1..2]="_C",true,false),indets(sol))

The above works, at least on the few examples I tried it on, but is there a better way to do it?  All constants will have the form _Cn where n is integer. 

Hi,

This question is related to the answer I gave to this question 232564-I-Need-To-Learn-What-Type-Of-Calculation

In a few words the OP (planetmknzm) wanted to know how a Maple's procedure (PlanePlot) was doing some calculus.
I proposed him to redirect the output of print('PlanePlot') to a mpl file, to open this latter, to insert a DEBUG() command and follow step by step what was going on.

If I execute the whole procedure (whose name is MyPlanePlot) I get this strange error
Error, (in MyPlanePlot) Colours is not a command in the Student package
Indeed PlanePlot contains instructions like this one

pl_Basis := plots['arrow']([[p, B[1]], [p, B[2]]], 'width' = pl_scale, 
      'colour' = Student:-Colours[2], op(basisoptions))

Searching for Colours in the help pages confirms what the error message says, but browsing the library with the assistant reveals that Student:-Colours does exist.

PlanePlot.mw

Do packages contain commands that are not accessible to users?
Why does PlanePlot work but its "clone" MyPlanePlot doesn't?
Last but not least, is there a way to fix this ?


Thanks in advance


PS : I discovered this issue as I was about to propose to planetmknzm another way to asked his previous question  232518-How-Can-We-Assign-The-Values-Of-Basis (just insert return B[1], B[2]: before the end of MyPlanePlot to get the vector basis)

restart;
Digits:=30:

f:=proc(n)
	x[n]-y[n];
	
end proc:


e1:=y[n] = (15592/1575)*h*f(n+5)+(35618816/99225)*h*f(n+9/2)-(4391496/15925)*h*f(n+13/3)-(2035368/13475)*h*f(n+14/3)-(212552/121275)*h*f(n+1)+(10016/11025)*h*f(n+2)-(31672/4725)*h*f(n+3)+(19454/315)*h*f(n+4)-(351518/1289925)*h*f(n)+y[n+4]:
e2:=y[n+1] = -(34107/22400)*h*f(n+5)-(212224/3675)*h*f(n+9/2)+(92569149/2038400)*h*f(n+13/3)+(82333989/3449600)*h*f(n+14/3)-(568893/1724800)*h*f(n+1)-(459807/313600)*h*f(n+2)+(1189/22400)*h*f(n+3)-(50499/4480)*h*f(n+4)+(32951/6115200)*h*f(n)+y[n+4]:
e3:=y[n+2] = (69/175)*h*f(n+5)+(1466368/99225)*h*f(n+9/2)-(13851/1225)*h*f(n+13/3)-(60507/9800)*h*f(n+14/3)+(43/3675)*h*f(n+1)-(3509/9800)*h*f(n+2)-(6701/4725)*h*f(n+3)+(871/420)*h*f(n+4)-(247/396900)*h*f(n)+y[n+4]:
e4:=y[n+3] = -(31411/201600)*h*f(n+5)-(745216/99225)*h*f(n+9/2)+(13557213/2038400)*h*f(n+13/3)+(9737253/3449600)*h*f(n+14/3)-(20869/15523200)*h*f(n+1)+(36329/2822400)*h*f(n+2)-(202169/604800)*h*f(n+3)-(100187/40320)*h*f(n+4)+(14669/165110400)*h*f(n)+y[n+4]:
e5:=y[n+13/3] = -(3364243/1322697600)*h*f(n+5)-(134364928/651015225)*h*f(n+9/2)+(19955023/55036800)*h*f(n+13/3)+(5577703/93139200)*h*f(n+14/3)-(910757/101847715200)*h*f(n+1)+(1336457/18517766400)*h*f(n+2)-(2512217/3968092800)*h*f(n+3)+(31844549/264539520)*h*f(n+4)+(690797/1083289334400)*h*f(n)+y[n+4]:
e6:=y[n+14/3] = -(29107/10333575)*h*f(n+5)+(7757824/651015225)*h*f(n+9/2)+(180667/429975)*h*f(n+13/3)+(342733/2910600)*h*f(n+14/3)-(7253/795685275)*h*f(n+1)+(42467/578680200)*h*f(n+2)-(19853/31000725)*h*f(n+3)+(993749/8266860)*h*f(n+4)+(22037/33852791700)*h*f(n)+y[n+4]:
e7:=y[n+9/2] = -(115447/51609600)*h*f(n+5)-(21389/198450)*h*f(n+9/2)+(231041241/521830400)*h*f(n+13/3)+(43797591/883097600)*h*f(n+14/3)-(32833/3973939200)*h*f(n+1)+(48323/722534400)*h*f(n+2)-(91493/154828800)*h*f(n+3)+(1220071/10321920)*h*f(n+4)+(24863/42268262400)*h*f(n)+y[n+4]:
e8:=y[n+5] = (1989/22400)*h*f(n+5)-(61184/99225)*h*f(n+9/2)+(1496637/2038400)*h*f(n+13/3)+(2458917/3449600)*h*f(n+14/3)+(73/5174400)*h*f(n+1)-(31/313600)*h*f(n+2)+(359/604800)*h*f(n+3)+(1079/13440)*h*f(n+4)-(179/165110400)*h*f(n)+y[n+4]:



h:=0.01:
N:=solve(h*p = 8/8, p):
#N := 10:
#n:=0:
#exy:= [seq](eval(i+exp(-i)-1), i=h..N,h):
c:=1:
inx:=0:
iny:=0:

mx := proc(t,n):
   t + 0.01*n:
end proc:

exy := (x - 1.0 + exp(-x)):

vars := y[n+1],y[n+2],y[n+3],y[n+4],y[n+13/3],y[n+14/3],y[n+9/2],y[n+5]:

printf("%6s%20s%20s%20s\n", "h","numy1","Exact", "Error");
#for k from 1 to N/8 do
for c from 1 to N do

	par1:=x[n]=map(mx,(inx,0)),x[n+1]=map(mx,(inx,1)),
		x[n+2]=map(mx,(inx,2)),x[n+3]=map(mx,(inx,3)),
		x[n+4]=map(mx,(inx,4)),x[n+5]=map(mx,(inx,5)),
		x[n+13/3]=map(mx,(inx,13/3)),x[n+14/3]=map(mx,(inx,14/3)),
		x[n+9/2]=map(mx,(inx,9/2)):
	par2:=y[n]=iny:
	res:=eval(<vars>, fsolve(eval({e||(1..8)},[par1,par2]), {vars}));
	
	printf("%7.3f%22.10f%20.10f%17.3g\n", 
		h*c,res[8],(exy,[x=c*h]),abs(res[8]-eval(exy,[x=c*h]))):
		#c:=c+1:
	
	iny:=res[8]:
	inx:=map(mx,(inx,5)):
end do:

Dear all,

Please Kindly help to correct or modify the code above

Thank you and best regards
 

how to plot call and put of classical Black Scholes with initial stock price 30, strike price 30 r=0.1, sigma=0.2 in  both Maple and MATLAB codes? how can we interpret the results?

Is there any one who knows what is behind of "PlanePlot"? How does it calculates the values below?

Hello :-)

I am trying to solve a third degree polynomial with assumptions, but I do not understand Maple's answers.

I think I am not doing it ''correctly''.

Can someone please help me understand why Maple gives me these answers and how I could get the ones that Maple gives me when I fix a value for my parameter t ? Please have a look at the attached file : test1.mw

I hope my questions are clear, please don't hesitate if you need clarifications.

Thank you very much for your help and your advices.

Why is this integral so difficult -- so slow to execute?

seq(evalf(Int(1/R*sinh(s*coth(1/2*s))^(2*I/k)/(gam-I*k*cosh(s))^5*
     Int(exp(-(k^2*sinh(s)^2/(gam-I*k*cosh(s))-I*k*(1+cosh(s)))*v)*
     hypergeom([1/k*I],[1],k*v*I)*v^n,v = 0 .. 1/2*R), s=0..s_max)), n=0..1);

Hints to improve the efficiency of execution would be appreciated.

The conversion of a maple formula in latex version 2021 produces some

commands which are not defined , see   primes_latex.mw.

Perhaps more informations should be given  in the news about the command latex in Maple 2021

I have a transfer function:

xfer_mag := 1/sqrt((-1.0000 + 1.0772*10^(-14)*f^2)^2 + (1.9665*10^(-20)*f^3 - 3.6181*10^(-6)*f)^2)

if I do:  semiplotplot(20*log[10](xfer_mag),f=10..30e6) I get :

but if I do: plot(20*log[10](xfer_mag), f = 10 .. 0.30e6), and then use the menu options to the right to change the axes properties to Log, I get this:

what is going on here?  why is the magnitude not the same ?

Download demo.mw

Hi everyone,

There is an attached file below. 

I am trying to solve the following equation and I get a numerical value with RootOf.

Do you know if it is possible to get the exact solution with RootOf? Do you know another method? In general, do you know a way to determine if Maple is able to get the exact value or not?

I know it is not always possible to get exact solutions, but maybe there is a way to do it for this polynomial... ? :--)

I hope my questions are clear. Thank you very much for your help and advices. 

test.mw

Hey folks;)

I'm new to Maple and as I tried to export my first document to PDF the plots changed. I tried  everything I could think of but nothing  worked.

All the labels on my plots are now at wrong positions.

I hope you can help me.

...I have to say to that I haven't bought maple yet so that could be a reason to try other progamms.

So thank you for your help    

I solve for a transfer function using Syrup, and want to operate on the Real part and Imagninary parts separately.  I've added "assumes" statements for every variable:  

assume(Rsrc, real);
assume(C1, real);
assume(Lp, real);
assume(C2, real);
assume(f, real);
assume(RL, real);
additionally(0 < Rsrc, 0 < C1, 0 < Lp, 0 < C2, 0 < RL, 0 < f);

When I then do something like :

 
instead of gettting just the real part of the expression, I get :

as if one of the variables was still not assumed to be Real.  I'm not sure where all the '~' are coming from ---is that the issue?

I apologize, I can't insert content for some reason..., although I can add the worksheeet.
pi_filter_osc_anal.mw

I have a function

f(x)=2*2^x-2

g(x)=-1/2x^2+3/2+5

When I plot by, plot(f(x),g(x) - no problem there.

But I need the intersection to continue my task and when trying to do f(x)=g(x) I get x=RootOf... back.

I've tried solve and a lot of other things, can anyone please help?

Thanks in advance

Best

Hello

I need to find all the variants (I am not sure if this is the correct term to be used but I hope this will be clear in the example) of a specific indeterminate in a given expression.  Here is an example:

alpha[3, 5]*xi[1]*xi[8] + alpha[3, 5]*xi[4]*xi[5] + alpha[3, 3]

For this particular example, xi[1], xi[8], xi[4], and xi[5] are the variables I am looking for. The indexes of xi change depending on the previous calculation.  Also, in some cases, I need the alpha variables instead, that is, alpha[3,5], and alpha[3,3].  

I could not figure out how to use indets in this case.

Many thanks for your help. 

I have a question? from the link: https://www.maplesoft.com/applications/view.aspx?SID=5084&view=html

How can we solve equation 2.1 to achieve solution 3.1 with boundary conditions explained in section " 1) Gaussian solution " ?
is this possible with maple?

Download pdsolve.mw