@RukevweOyinloye One thing that you certainly must do is remove the minimize from the objective function. The Optimization[Minimize] already specifies that you want to minimize.

You probably have other problems also, which'll be easier to diagnose when you upload a worksheet.

@nm That _Z is the bound variable of RootOf​​​​​, and every RootOf has a _Z, so you'd might as well just filter out all occurences of RootOf. That _Z is very different from the free variables returned by discont, solve, etc., that you're otherwise looking for.

@Carl Love Some commands may also return unknown functions, such as _F(x, y). For example, pdsolve might do this. These can be filtered by type typefunc(suffixed('_')) as the 2nd indets argument. To filter both symbols and functions, make the type 

{thistype, typefunc}(suffixed('_'))

To filter indexed names as well, make it

{thistype, typefunc, typeindex}(suffixed('_'))

@Thomas Dean You can use until testeq(...)=FAIL instead of the overly complicated 
until evalb(testeq(...)=FAIL).

@Thomas Dean Sorry, you were right; there is a difference. I think that the presence of a difference in how while and until handle FAIL should be considered a bug in the implementation of until.

@Thomas Dean There is no difference in how if, while, and until interpret FAIL! They all interpret it the same as false.

@Preben Alsholm You can also do

TypeTools:-AddType(ID, ()-> try type(args) catch: false end try);

@tim_finks Sorry that I didn't notice that this was about Maple Flow instead of Maple.

@nm Yes, you're right about numelems. I'll correct the Answer. I did know this, but I was momentarily fooled by the coincidence of both values being 3. Thank you for spotting that.

@eithne I have the correct Build ID. Nonetheless it confusied me because it's dated Nov 24, 2023. I see now that's a later date than the announcement of Maple 2023.2, but that was not obvious at first.

@nm I think this is what happened: I installed my Maple (on a brand new computer) yesterday at about 1:30 PM (EST). As usual, I had it check for updates during the install. The Post at the head of this thread was made at 2:06 PM (EST), after I installed. But I guess the update was already available some short time before the Post, so I got it with my install.

Yes, this whole confusion could be avoided if Maple just said the complete version number.

@nm I tried the menu option Tools => Check for Update, but it said that I already had the latest version.

@mmcdara It's easy to make this mistake given the Question's title. I made it myself,.but I noticed it while posting my tentative Answer. The OP wants to know the values of beta and f for which there are three (or more?) extrema. I don't know what "consecutive" means in this context.

I downloaded the update, and tried to install it, but it refused, saying "You've already upgraded to Maple 2023.2".

This isn't your fault, but MaplePrimes doesn't correctly upload ".maple" workbooks. Would you please put the files together in a ".zip" file and upload that? Let me know if you don't know what a ".zip" file is (or a websearch will tell you and lead you to a free utility for making them).