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Question: are c__1 and _C1 no longer same object in Maple 2025.1?

Question:are c__1 and _C1 no longer same object in Maple 2025.1?

nm 11503 Maple 2025
programming
3 hours ago
0

The nice addition added to Maple 2022 in this  post made it clear that c__1 and _C1 are the same under the cover.

But then why in Maple 2025.1 it does not give this?

I found this when I was trying to find constants of integrations in solution of an ode, and used 

                 indets(sol,And(symbol, suffixed(_C, nonnegint))); 

Which did not find the constants of integration, since I happened to have typed the solution using c__1 and not _C1, but I thought they are the same.

Did something change or I still dont understand well the difference between c__1 and _C1 ?

Worksheet below.

> 

interface(version);

`Standard Worksheet Interface, Maple 2025.1, Linux, June 12 2025 Build ID 1932578`

> 

SupportTools:-Version();

`The Customer Support Updates version in the MapleCloud is 29 and is the same as the version installed in this computer, created June 23, 2025, 10:25 hours Eastern Time.`

> 

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1881 and is the same as the version installed in this computer, created 2025, October 7, 16:4 hours Pacific Time.`

> 

restart;
> 

sol:= y(x)=-cos(x)/2+sin(x)/2+c__1*exp(-x);
indets(sol,And(symbol, suffixed(_C, nonnegint)));

y(x) = -(1/2)*cos(x)+(1/2)*sin(x)+c__1*exp(-x)

{}

> 

sol:= y(x)=-cos(x)/2+sin(x)/2+c__1*exp(-x);
indets(sol,And(symbol, suffixed(c__, nonnegint)));

y(x) = -(1/2)*cos(x)+(1/2)*sin(x)+c__1*exp(-x)

{c__1}

> 

sol:= y(x)=-cos(x)/2+sin(x)/2+_C1*exp(-x);
indets(sol,And(symbol, suffixed(c__, nonnegint)));

y(x) = -(1/2)*cos(x)+(1/2)*sin(x)+_C1*exp(-x)

{}

> 

sol:= y(x)=-cos(x)/2+sin(x)/2+_C1*exp(-x);
indets(sol,And(symbol, suffixed(_C, nonnegint)));

y(x) = -(1/2)*cos(x)+(1/2)*sin(x)+_C1*exp(-x)

{_C1}

> 

c__1 - _C1

c__1-_C1

> 

addressof(c__1);

36893628553737883996

> 

addressof(_C1);

36893628553623934140

> 

 


 

Download why_c1_and_C1_not_same_oct_19_2025.mw

Update

Found out why. This only works if one calls dsolve() first.  Here is an example

> 

sol:=dsolve(diff(y(x),x)=x)

y(x) = (1/2)*x^2+c__1

> 

c__1 - _C1;

0

> 

indets(sol,And(symbol, suffixed(_C, nonnegint)));

{c__1}

> 

restart;
> 

my_sol:=y(x)=(x^2)/2+c__1;

y(x) = (1/2)*x^2+c__1

> 

c__1 - _C1;

c__1-_C1

> 

indets(my_sol,And(symbol, suffixed(_C, nonnegint)));

{}

> 

 

 

Download why_c1_and_C1_not_same_oct_19_2025_V1.mw

But this is really confusing. c__1 before calling dsolve is not the same as c__1 after calling dsolve.

It will be better if Maple is changed such that these work the same all the time without having to call dsolve() first.

 

 

 
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