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Messages - sailerboy
1
« on: December 05, 2013, 12:52:53 am »
Ran out of batteries and got now charger, and I'm not willing to make a makeshift cable, I'm a software guy not hardware. 
And you don't have any micro usb cable sitting around? I can count on 1 hand the times I've used the "official" charger. It will charge just as well from any usb port...
The Hp Prime does not use a micro usb cable, it is a very specific port made for an Hp Prime cable only. I would have tried that already I have more than 50 micro usb cable.
Dude, it's a microusb. Tim Wessman works for HP on the prime, he would know exactly what the prime uses...
2
« on: December 03, 2013, 01:44:13 pm »
Among many other things, I really like how ex shows up properly now, instead of just exp(x). Some other things look like they have been fixed too. The lack of implicate multiplication is still very annoying though.
3
« on: October 19, 2013, 02:02:51 am »
It's been a while since I've posted, but I'm back. One thing that's really bugged me is the simplify feature. In certain instances, it seems to make things much more complicated. I know that this is a bad example, since it's already as simplified as possible, but it illustrates what I mean:  Here's a better one:  I would expect the calculator to combine the 5 and the 1/11 to make 5/11, or some other simplified thing. I'm not sure what the fascination of putting everything under the log is, it certainly doesn't make it easier to read, write, or type. Also, when's the OS update coming out? The way Tim talks about it makes it seem that some, perhaps many of these issues are already fixed.
4
« on: September 28, 2013, 01:48:38 pm »
I'm using the Prime's OS that it came with. There hasn't been an update, has there?  EDIT: I tried redefining, and it seemed to work. Strange...
5
« on: September 28, 2013, 01:12:58 pm »
I've got another question that may seem simple. How does one do Polynomial division?
For example, I entered (x^7+4x^3+8)/(x^2+2) in the cas mode, and it just rewrites it as a fraction. I tried using "simplify()", but that doesn't change it at all. To do division, I have to go to the on screen menu, select CAS, select Polynomial, Algebra, Quotient, and input the function, but even then, I get "Gen [int] Error: Bad Argument Type"
It seem that XCAS has no function implemented that does what you want, i.e. 'divide out' 2 polynomials (or a ratio of 2 polynomials).
Most other CAS have such a function (e.g. 'divout'), but you can define such a function yourself in the HP-Prime CAS:
divout(p):=quo(numer(p),denom(p))+rem(numer(p),denom(p))/denom(p)
Now if you enter divout((x^7+4x^3+8)/(x^2+2)) you get exactly what you want - an 'integer' part of the polynomial division and a 'remainder' part.
Franz
How do you define a function? I tried using f(a,b) := <function>, but it turned that into "table(a,b = <function>)"
6
« on: September 28, 2013, 12:17:31 am »
Another bug: Trying to differentiate the equation (2/3)(x^2+1)^(3/2) gives weird output. Here is the image:  And here is the expected result: http://www.wolframalpha.com/input/?i=differentiate+%282%2F3%29%28x%5E2%2B1%29%5E%283%2F2%29Also, with the TI Nspire, i was able to quickly and easily able to create functions for certain math problems, like so: f1(x,a,b):=x^2+ax+b And for any value I then typed in for x, a, and b, it would substitute that in the equation. Is there an easy way to do something like this in the Prime?
7
« on: September 27, 2013, 05:23:43 pm »
That seems like a lot of steps to get to something that occurs fairly often. Why can't I just do (polynomial 1)/(polynomial 2) for division?
Is your Simplify level on Off? If it is, remember that the CAS won't change your variables at all. I always have it on Maximum.
I have simplify off since CAS does weird things sometimes, but there's the simplify button on the screen. I tried pushing that and it had no effect.
8
« on: September 27, 2013, 04:47:30 pm »
Nearly there. Put your first poly in the first argument, and the second in position 2. Just like the nspire, it is a 2 argument function.
quo(x^7+4x^3+8,x^2+2)
That seems like a lot of steps to get to something that occurs fairly often. Why can't I just do (polynomial 1)/(polynomial 2) for division?
9
« on: September 27, 2013, 01:24:37 pm »
I've got another question that may seem simple. How does one do Polynomial division?
For example, I entered (x^7+4x^3+8)/(x^2+2) in the cas mode, and it just rewrites it as a fraction. I tried using "simplify()", but that doesn't change it at all. To do division, I have to go to the on screen menu, select CAS, select Polynomial, Algebra, Quotient, and input the function, but even then, I get "Gen [int] Error: Bad Argument Type"
I know that this was alluded to in Cemetech's review of the HP Prime, but he never really gave a solution for the problem beyond just saying that it was an indescriptive error.
Also, one thing I just noticed: If I wanted to find the limit of, say, 1/x as x goes to zero from the positive side, I have to enter "1" instead of just entering "+", likewise if i wanted to find it from the negative side, I would have to enter "-1" instead of just "-".
10
« on: September 26, 2013, 08:27:31 pm »
Thank you. The integrated system-wide help stuff is actually one of the most ambitious parts of the whole system and it is just so darn easy to miss places because of the sheer volume.
Since there are so many bugs and feature requests, I just wanted to say, this is my favorite part about the calculator, that I don't have to go digging through a manual to figure out how something works.
11
« on: September 26, 2013, 11:21:04 am »
Delta is a quite well-used greek letter used in almost any science topic, though (math, physics, chemistry...)
Thats what sad with US education, I guess
(I can actually judge since I've spent one year there (senior year in HS, with an AP Calculus class), and did the rest of my scolarity in France)
I use delta all the time! We tend to use Δ as the symbol for delta, not ∂ though. Wikipedia says it's an old style way of writing it (though it's greek, so any letter is "old"). In terms of derivatives and integrals, instead of using Δ we tend to use "d", as Δ implies "change in a quantity", which is generally an expressible value. Using "d", on the other hand, implies an infinitely small value. I'm also familiar with the "prime" notation (eg. (x^2)'=2x), though less so, since I'm an engineering major, so we tend to use the d/dx format more often.
12
« on: September 26, 2013, 12:16:38 am »
However, in the template, I only see the notation for a partial derivatives, which is not something I was used to.
Out of curiosity, where in the world approximately are you from? I personally prefer the d/dx*() syntax (USA here), but apparently the majority of the world uses the d()/dx syntax much more frequently (at least from the studies we've done).
I'm from the good ole US of A (California if you want to be precise). I've only ever learned the d/dx*() syntax. I've certainly never seen the ∂ character before. When I looked it up on wikipedia (by searching for "upside down 6"), I got this article: http://en.wikipedia.org/wiki/Partial_derivativeThis notation for partial derivatives were certainly not something I've ever seen in math class before, and at first glance, the notation confused me. I'm currently a math minor in university, and I've taken several upper division math classes, and though I've seen the concept of partial derivatives (that's a Calc 1 topic IIRC), I've never seen that notation before. Would it be hard to, on startup, ask the user's locale? Say, American English vs British English vs Australian English all have their own quirks, and while the differences would be minor, it would prevent confusion like this.
13
« on: September 25, 2013, 07:23:58 pm »
Another thing was, how the heck are you supposed to take a derivative? Whatever way it was coded is definitely not intuitive.
You've lost me on this one. There are 3 quite easy ways. Press CAS to switch to symbolic mode, open the template, select the d<box>/d<box> template, type it in. Or else type diff(func, var), or just sin(x)'
Are you in the HOME screen? If so, you are probably using X which is a predefined real number, instead of 'x' which would be a symbolic object with no definition.
In home d(sin(X),X=<num>) would let you do a numerical at a specific point.
Oh, and last edit... did you try selecting the "differentiate" from the CAS->calculus and clicking the HELP key. That would pop up more info.
This was a result of me being with TI for so long, I've gotta admit. However, in the template, I only see the notation for a partial derivatives, which is not something I was used to. I didn't see the d<box>/d<box> thing that you're thinking of, just this: ∂<box>/∂<box> I'll upload a picture of that screen just to make sure that I'm in the right place when I get home. Trying to type the ' without typing degrees first was challenging. I could use the diff notation (and actually, I forgot about it), but it comes up so much I was hoping for a shortcut like the integral.
14
« on: September 25, 2013, 09:45:10 am »
Another thing was, how the heck are you supposed to take a derivative? Whatever way it was coded is definitely not intuitive.
15
« on: September 23, 2013, 11:35:18 am »
If you've got a larger case, you may as well go with an ATX motherboard. They are generally higher quality and cheaper than MicroATX, as well as being more extensible.
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