|Re: HP-Prime: issues in entering expressions|
Message #15 Posted by Han on 29 Sept 2013, 8:42 p.m.,
in response to message #13 by parisse
Here is what's wrong with allowing implicit multiplication:
1. Create a program with the following code:
F0:="X-F1(X)/" + diff(F1(X),X);
2. Enter in 'X^3-8' into F1.
3. Run the program and then check F0 in Symb view.
The code above should have worked -- but it doesn't because diff does not return the result with an unnecessary extra set of parentheses. In order to properly form F0, one has to do:
F0:="X-F1(X)/(" + diff(F1(X),X) + ")";
The trailing +")" can be left off if we want to do some lazy coding. The benefit of now being able to leave off ()'s in 1 or 2 minor cases does not warrant leaving many users frustrated that they are getting "unexpected" results when pretty much every other similar system DOES NOT allow this sort of implicit multiplication. In fact, it flies in the face of the order of operations. Based on
Also, from a pedagogical point of view, we are NOT helping students AT ALL by enabling them to lazily type 1/2x and get 1/(2x). If the HP Prime is really supposed to help students learn mathematics, then this minor "feature" is actually a step backward insofar as helping them learn order of operations.
I can appreciate that Xcas may be faster than commercial alternatives. However, if it means that users are going to have to always keep an extra set of manuals lying around because it's the one system that does not behave anything like the other ones, I would wager many would simply forgo using Xcas. Because let's face it -- even if Maple were slower, it's cheaper to buy a faster machine and run a familiar piece of software than to spend that extra time having to learn the idiosyncrasies of a competing software. The time saved by faster computations is completely nullified by the time it takes to learn the nuances of Xcas. One need only look at how poorly the RPN graphing calcs have done in the US classrooms. I wholeheartedly believe that the HP50G is still the best calc -- but you won't win over the education market in the US by forcing RPN down everyone's throats. Even more telling is the fact that the HP Prime has put RPN as a secondary option ever since the HP 50G. My point is, Xcas may be superior in many ways -- but unless it is as easy to use as the current commercial offerings with little to no learning curve, it will always play catch up in terms of market share.
Lastly, I also find it hard to believe that students in high school or even college would require calculations such that the speed difference given by using Xcas on a calculator would even be noticeable. Most of the problems they will ever face in a class tend to be easily handled by basic programming. If speed were ever really a factor, then even if they used Xcas it would be done on a much more powerful computer and not a handheld.
Edited: 29 Sept 2013, 10:20 p.m.