nm

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These are questions asked by nm

For compution this is not important, for latex, I find  n>0 little more clear to read than 0<n 

Is there a way to tell Maple not to reverse terms on each side of the > just for latex purposes?

It seems Maple does this only for   > and not for  <

I know the latex output follows what is displayed on the screen in Maple. And that is what happens also for display. Maple rewrites n>0 as   0<n.   

I tried changing display->Typesetting level from extended to maple standard but this had no effect. 

Is there a trick to make Maple not all the > to  <  ?

Again, I wanted to do this just for the latex output because for computation and for screen display in worksheet, it is not an the issue for me, as I only use Latex output.

It seems Maple like to make everything  based on "<" internally and that is why it reverses it?

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

restart;

latex(n>0,'output'='string'); #why this is reverse on output?

"0<n"

latex(n>m,'output'='string'); #why this is reverse on output?

"m <n"

latex(n<0,'output'='string'); #but this stays the same

"n <0"

latex(n<m,'output'='string'); #but this stays the same

"n <m"

n>0

0 < n

 

 

Download why_reverses_may_1_2025.mw

This happens in Maple 2025, but when I checked Maple 2024.2, same thing happen.

To reproduce, I typed ?coeff in the worksheet. Now the help page for coeff comes up OK. On the right, there are some links below "see also". 

Clicking on the one that says PolynomialTools[CoefficientVector] and now an EMPTY page opens up.

Also, typing ?PolynomialTools in worksheet, opens the help page for Overview of the PolynomialTools Package. Now clicking on CoefficientList link, opens an EMPTY page. Same when clicking on CoefficientVector, an EMPTY page !

Have not checked all the links in the help page, but why are some commands have empty help pages?

 

 

The series to ode using 'series' option (if it exists) should always be series(...), i.e. with big O at end. but sometimes Maple forgets to add this. Here is an example

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1862 and is the same as the version installed in this computer, created 2025, April 25, 10:33 hours Pacific Time.`

SupportTools:-Version();

`The Customer Support Updates version in the MapleCloud is 15 and is the same as the version installed in this computer, created April 27, 2025, 23:18 hours Eastern Time.`

restart;

ode:=diff(y(x),x)+y(x)=1+x;
IC:=y(0)=0;
sol:=dsolve([ode,IC],y(x),'series')

diff(y(x), x)+y(x) = 1+x

y(0) = 0

y(x) = x

lprint(sol); # notice solution is not series, it should be

y(x) = x

#above solution should be
y(x) = series(x+O(x^6),x,6)

y(x) = series(x+O(x^6),x,6)

#this example below is correct
ode:=diff(y(x),x)+y(x)=1+x;
IC:=y(0)=1;
sol:=dsolve([ode,IC],y(x),'series')

diff(y(x), x)+y(x) = 1+x

y(0) = 1

y(x) = series(1+(1/2)*x^2-(1/6)*x^3+(1/24)*x^4-(1/120)*x^5+O(x^6),x,6)

lprint(sol); #solution is series

y(x) = series(1+1/2*x^2-1/6*x^3+1/24*x^4-1/120*x^5+O(x^6),x,6)

 

 

Download bug_report_dsolve_series_april_28_2025.mw

These two expressions are the same, just pulled minus sign out

But look what happens when integrating them. the anti derivative of one is much more complicated than the other and contains complex numbers and logs. And no matter what I tried, I could not convert the complicated one to look same as the simpler result. Also could not verify the complicated one by back differentiating.

integrand_1:=x^2*(-arctan(x) + x)*exp(-arctan(x) + x)/(x^2 + 1);

x^2*(-arctan(x)+x)*exp(-arctan(x)+x)/(x^2+1)

integrand_2:=evala(integrand_1);

-x^2*(arctan(x)-x)*exp(-arctan(x)+x)/(x^2+1)

simplify(integrand_1 - integrand_2)

0

anti_1:=int(integrand_1,x);

(-arctan(x)+x)*exp(-arctan(x)+x)-exp(-arctan(x)+x)

anti_2:=int(integrand_2,x);

-(1-x+((1/2)*I)*ln(1-I*x)-((1/2)*I)*ln(1+x*I))*(1-I*x)^(-(1/2)*I)*(1+x*I)^((1/2)*I)*exp(x)

simplify(diff(anti_1,x)-integrand_1);

0

simplify(diff(anti_2,x)-integrand_2);

Error, (in simpl/simpl/ReIm/sum) too many levels of recursion

simplify(anti_1 - anti_2)

Error, (in simpl/simpl/ReIm/sum) too many levels of recursion

simplify(anti_2);

(1/2)*(I*ln(1+x*I)-I*ln(1-I*x)+2*x-2)*(1-I*x)^(-(1/2)*I)*(1+x*I)^((1/2)*I)*exp(x)

simplify(anti_2,ln);

(1/2)*(I*ln(1+x*I)-I*ln(1-I*x)+2*x-2)*(1-I*x)^(-(1/2)*I)*(1+x*I)^((1/2)*I)*exp(x)

 

 

Download int_strange_result_april_27_2025.mw

I would have expected same anti derivative to show.  To check, I used another software, and that one gave same anti-derivative for both integrands.

The questions I have: Why Maple gives such different result for same integrand? And how could one convert the one with the logs and complex numbers to the first one?

Maple 2025

FYI;

 

You might have to try the command more than one time to see the above crash. Here is the worksheet

restart;

interface(version);

`Standard Worksheet Interface, Maple 2025.0, Linux, March 24 2025 Build ID 1909157`

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1862 and is the same as the version installed in this computer, created 2025, April 25, 10:33 hours Pacific Time.`

SupportTools:-Version();

`The Customer Support Updates version in the MapleCloud is 13 and is the same as the version installed in this computer, created April 22, 2025, 15:14 hours Eastern Time.`

restart;

ode:=x^2-2*x*y(x)+5*y(x)^2 = (x^2+2*x*y(x)+y(x)^2)*diff(y(x),x);

x^2-2*x*y(x)+5*y(x)^2 = (x^2+2*x*y(x)+y(x)^2)*(diff(y(x), x))

sol:=y(x) = (-1/2*exp(RootOf(-exp(_Z)^2*ln(x*(exp(_Z)-2))+2*_C7*exp(_Z)^2+_Z*exp(_Z)^2+4*exp(_Z)*ln(x*(exp(_Z)-2))-8*_C7*exp(_Z)-4*exp(_Z)*_Z-2*exp(_Z)-4*ln(x*(exp(_Z)-2))+8*_C7+4*_Z+6))^2+3*exp(RootOf(-exp(_Z)^2*ln(x*(exp(_Z)-2))+2*_C7*exp(_Z)^2+_Z*exp(_Z)^2+4*exp(_Z)*ln(x*(exp(_Z)-2))-8*_C7*exp(_Z)-4*exp(_Z)*_Z-2*exp(_Z)-4*ln(x*(exp(_Z)-2))+8*_C7+4*_Z+6))-6+2*(exp(RootOf(-exp(_Z)^2*ln(x*(exp(_Z)-2))+2*_C7*exp(_Z)^2+_Z*exp(_Z)^2+4*exp(_Z)*ln(x*(exp(_Z)-2))-8*_C7*exp(_Z)-4*exp(_Z)*_Z-2*exp(_Z)-4*ln(x*(exp(_Z)-2))+8*_C7+4*_Z+6))^2-6*exp(RootOf(-exp(_Z)^2*ln(x*(exp(_Z)-2))+2*_C7*exp(_Z)^2+_Z*exp(_Z)^2+4*exp(_Z)*ln(x*(exp(_Z)-2))-8*_C7*exp(_Z)-4*exp(_Z)*_Z-2*exp(_Z)-4*ln(x*(exp(_Z)-2))+8*_C7+4*_Z+6))+9)^(1/2))/(1/2*exp(RootOf(-exp(_Z)^2*ln(x*(exp(_Z)-2))+2*_C7*exp(_Z)^2+_Z*exp(_Z)^2+4*exp(_Z)*ln(x*(exp(_Z)-2))-8*_C7*exp(_Z)-4*exp(_Z)*_Z-2*exp(_Z)-4*ln(x*(exp(_Z)-2))+8*_C7+4*_Z+6))^2-3*exp(RootOf(-exp(_Z)^2*ln(x*(exp(_Z)-2))+2*_C7*exp(_Z)^2+_Z*exp(_Z)^2+4*exp(_Z)*ln(x*(exp(_Z)-2))-8*_C7*exp(_Z)-4*exp(_Z)*_Z-2*exp(_Z)-4*ln(x*(exp(_Z)-2))+8*_C7+4*_Z+6)))*x:

odetest(sol,ode);

 

Download crash_maple_2025_april_27_2025.mw

Hopefully a fix could be found for this.

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