Given first order nonlinear ode which is hard to solve using standard methods, the smart dsolve sometimes uses a method where it linearizes the first order ode to a linear second order ode and solves that.

Then with that solution to the linear second order ode, it is able to find the solution of the first order ode (need to resolve the constants of integration to merge them into one, but this part is easy to do).

My question is, how and what method it uses to "linearizes by differentation"? I could not find this in any textbook I have, and not able to see how it does.

Here is an example where it uses this method to solving this first order ode

restart;

Typesetting:-Unsuppress('all'); #always do this.
Typesetting:-Settings(prime=x,'typesetprime'=true); #this says to use y'(x) instead of dy/dx    
Typesetting:-Suppress(y(x)); # this says to use y' and not y'(x)

ode:=diff(y(x),x) = (-y(x)^2+4*a*x)^2/y(x); 
infolevel[dsolve]:=5;
dsolve(ode,y(x), singsol=all);

Tracing says 

So it says, if I understand, that it differentiated the original given first order ode and then linearized the resulting second order ode to the above, which is    y''=-64 a^2 x^2 y - 16 a x y' which is certainly linear second order ode and now can be solved using kovacic algorithm. Now the solution to the first order ode can be obtained.

But when differentiating the first order ode, this is the result

expand(diff(ode,x))

So the question is, did Maple mean it "linearized" the above to y''=-64 a^2 x^2 y - 16 a x y' ? 

If so, then how? Did it use Taylor series? but if so, where it expanded about? Or did it use some other method?  One thing I noticed is that by multiplying the RHS above by y^2 it becomes

And "removing" the nonlinear terms (say expansion is around y=0, so higher order y terms are very small and can be removed) the RHS above becomes

    y'' y^2 = -16 y' a^2 x^2 + 32 a^2 x y

Which is close to Maple shows, but 32 instead of 64, and what about the y^2 on the left side?  Is this method even valid mathematically to do? Since solution that result will be correct only near y=0?

So far, trying to step in the debugger to find how, I was not able to find where it does that but will keep trying.

Any idea what Maple means by linearization to 2nd order and how it does it?

ps. only case I know about, where nonlinear first order ode can be transformed to linear second order ode is the Riccati ode using transformation y=u'/u. But this  first order ode is not Riccati.

This is a question on semantics I suppose.

Maple dsolve returns a solution with a limit in it, because the limit do not exist or Maple could not find the limit. Which is fine.

Then why does simplify() applied to the solution returns undefined?  Now it appears that Maple solution is y(x)=undefined, which does not make much sense.

Should it not have left the solution with the limit in place as is? i.e. since dsolve could not find limit, how did simplify managed to replace the limit by undefined?

Is this considered an expected behavior by simplify?

Firewall changed its mind again today and will not let me upload worksheet. Here is code

ode:=4*x*diff(y(x),x$2)+2*diff(y(x),x)+y(x)=(6+x)/x^2;
IC:=y(infinity)=0;
sol:=dsolve([ode,IC],y(x)); #OK, maple can't find limit. No problem
simplify(sol)

I have to ask my school teacher on this when school starts. But is it OK to have infinity in the ode solution itself?

Maple 2025.2 gives

ode:=diff(y(x),x$2)-2*diff(y(x),x)+y(x)=4*exp(-x);
IC:=y(infinity)=0;
sol:=dsolve([ode,IC])

And according to odetest, this does not verify the ode nor the IC

odetest(sol,[ode,IC])

Just asking what others think of this solution and if it should be consider a bug or not?

Maple 2025.2 on windows 10

Solving this ode, Maple says 

But notice, the xi and eta tangent vectors order is reversed. Maple says pattern is [0,F*G], but shows [F*G,0].

Also, when later using DEtools:-symgen with HINT option, it does not return the above result. Tried both patterns with 0 on left and 0 on right. In both cases symgen does not return what shows above. 

Why is that? Am I doing something wrong? Notice also it says   "way=HINT"  but I am not using way option. Only HINT option, Why is it saying way=HINT? it seems argument passing I  am using is wrong, but do not see why it could be wrong.  This is what help says

Worksheet below

Download symgen_confusion_jan_9_2026.mw

I was searching release notes for some old Maple versions. I found so many broken links on Maple web pages. The first page is https://www.maplesoft.com/products/maple/history/ 

Scrolling down, and starting from Maple 2016 (about half way down the page), all links to the "product press release" are broken. This is the link to the right of each product.  All these links on the right, from 2016 to the end of the page are broken,

Clicking on any of these, sends the user to new broken web page, called https://www.maplesoft.com/company/publications/  titled "Maplesoft media coverage".

This page does not even work. Clicking on "Jump to year" does not open. Clicking in "first page" does nothing. Tried Edge browser on windows 10, also the page does nothing. 

Then I clicked on Maplesoft Media Releases link at top, and now it works.

But jumping to any year before  2016, all the links that show on those pages are broken. Try and see,

For example. jumping to 2015, and clicking on release called "

November 25, 2015"

Gives

This applies to each press release for each year from 2015 to 1997.

Hundreds of links are broken.

There is software which checks broken links, and it is free for windows, called Xenu's Link Sleuth. May be someone at Maplesoft can use it to find all broken links at Maplesoft web site and fix them?

It is not acceptable in this day and age to have a Major software company with a web site full of broken links.