Previous 1 2 Next 21 Replies Latest reply: Oct 29, 2007 12:38 PM by jaxjason
jaxjason Level 4 Level 4 (3,460 points)
I am trying to help my wife with her Precalculus class. So far I have done some very very basic y=mx+b type thing (y=3x-b, b={1...5}) worked nice. But I need alot more thn I am finding out there. Somebody has got to know how to use this program. Its really great, But the examples are way too complex for what I am trying to figure out.

example: plot the same equation, but only plot for x>3<=9 I cannot find anything on this.
Please help,
Jason

Power Mac Dual 2.0 G5, Mac OS X (10.4.10)
  • baltwo Level 9 Level 9 (61,945 points)
    IIRC, everything you need is contained in the Help files. Alternatively, search these forums and google for grapher.
  • jaxjason Level 4 Level 4 (3,460 points)
    IIRC, everything you need is contained in the Help files. Alternatively, search these forums and google for grapher.


    huh? IIRC? Sorry, don't know that one. And i have read the entire help file. Once again the examples are quite complex compared to what I am trying to do. btw, they are about thirty total pages of help files. pretty useless really considering almost half have to do with appearance of the graphics.

    Googled already. not a whole lot except people saying they cant find anything either. Searched on here. other than someone that didn;t have it and a reference to the old OS9 version of the software everyone theorizes it was based upon, nothing.

    I am always helping on other boards here. Already did the research I would be expected to do, both here and Google. nothing. Now I am asking for others that might have good examples or personal web pages explaining the stuff. Anything that might help would be greatly appreciated.

    Thanks alot for your suggestion though,
    Jason

    Edit: just googled IIRC, sorry didn't remember that one. Got it now. Thanks.

    Message was edited by: jaxjason

    Message was edited by: jaxjason
  • baltwo Level 9 Level 9 (61,945 points)
    Then your search has proven that there's not much out there. Maybe, if you posted exactly what you're trying to do, but can't, you'd get some help. Sorry, but I know about as much as you do.
  • jaxjason Level 4 Level 4 (3,460 points)
    From original post...
    y=3x-b, b={1...5}
    plot the same equation, but only plot for x>3<=9</div>

    Sorry, It must have gotten lost in the post.

    I have figured out how to plot basic equations, but not limit them to specific ranges of numbers. The examples are just too complex, with no explanation of why they typed what they typed.

    I was posting here because this is where the most knowledgeable people are concerning this type of thing, and they might have personal pages, or knowledge that is not searchable on google.

    Thanks for the feedback,
    Jason
  • 5|=vv Level 3 Level 3 (685 points)
    I know that "Graphing Calculator" could do this, an awesome program (see http://www.pacifict.com/), but potentially pricey depending on you situation.

    In Grapher, though, I have only been able to get close:

    (1) This will honor one boundary, but I'm unable currently to figure out how to incorporate a second condition:

    y=x>3:3x-b,b={1....5}

    (2) There is also in the "Operators" part of the "Equation Palette" a "Condition" operator. This could be promising. I was able to get close with two equations, first:

    b={1...5}

    and second a three part condition:

    x ≤ 3 0
    x > 9 0
    x >0 3x-b

    This, though, leaves unsightly lines plotted on top of the x axis outside the 3>x≥9 range.

    If I come up with something better, I'll post again.
  • baltwo Level 9 Level 9 (61,945 points)
    When I paste y=3x-b, b={1...5} into Grapher, I get a syntax error. Not having played with, I'm out of my depth. Good luck.
  • jaxjason Level 4 Level 4 (3,460 points)
    give me a screen shot. I can probably find where it went wrong.

    Jason
  • jaxjason Level 4 Level 4 (3,460 points)
    yeah, I'm looking to use the free version that we already have.

    I did find this link that I think will explain it. Took me about a hundred searches to find it though. (have to wait till I get home.)

    Grapher question

    It looks like your on the right path. Your first example looks like the sample in the link I put here. I don't quite get what its doing or why its typed like that yet, but if I can figure this out, I will post it here and in the other post too.

    thanks for the info so far,
    Jason


    hey I finally got to give 5|=vv some points!!!

    Message was edited by: jaxjason
  • 5|=vv Level 3 Level 3 (685 points)
    Jason-

    Your link was just the ticket. Here are two ways, now, to solve your problem:



    I'm not sure, exactly, how to tell explain how each was created. The second one is pretty straight forward to type as you see it. The "hat" symbol, as indicated in your link, must be entered from the "Symbol" panel of the "Equation Palette".

    The first one is using the "Conditional" operator from the palette with a single condition. This creates the curly left brace with two seed locations. In the left seed location you enter the condition, just like the second one, "hat" and all. In the second seed goes the line equation and the b value set. Actually, the b value set and its preceding comma separator can go after the second seed location, if you like. The difference is subtle and there is no difference in the resulting graph.

    In the case of the second one, this is a degenerate form of notation I'm familiar with: a piece-wise function. Normally there are two or more conditional phrases. Each phrase specifies a range of values for which the subsequent expression is defined. In this degenerate case, it is saying that 3x-b is only defined for the values in the range [3..9).

    The stumbling block here was how to express 3≤x<9 in the condition. Your link held the key in that it must be expressed as the intersection of the two conditions, intersection being a standard meaning of the "hat" symbol.
  • jaxjason Level 4 Level 4 (3,460 points)
    I was having a hard time visualizing what the poster was saying. Your explanation was much better. Now i have a little bit of a clue. But you have to be really careful it seems. Just like programming, one tiny mistake or typo, and its all bets are off.

    Gotta go, wife has class @ 8 online.

    Thanks alot 5|=vv
    Jason
  • baltwo Level 9 Level 9 (61,945 points)
    When I enter either of those equations into Grapher, using the equation palette and keyboard, I get a syntax error. Very confusing using the conditional operator. Get a bracket and two vertical lines, but don't know where to type anything, and nothing closes the bracket. There's no rhyme or reason to using the palette. Thoughts?
  • 5|=vv Level 3 Level 3 (685 points)
    For the conditional operator, the bracket doesn't close... see my screen shot above. When you create a conditional operator with a single condition (by entering 1 into the resulting dialog box), you get a bracket and "two vertical lines", as you said. These vertical lines are actually narrow gray boxes that indicate where additional input is required (I referred to them as "seeds", above). You can click on each one separately and enter the require "phrases" as I have tried to explain above. Doing so replaces the seeds. Does this help?
  • baltwo Level 9 Level 9 (61,945 points)
    Every little bit helps, because the usage is arcane; however, I don't have time to pursue this further today. I sort of understand the seed bit, but then how do you close the conditional and put in the actual equation? When I tried using x>3^x<9 3x+5 after the conditional, I kept getting the syntax error. More experimenting is in order.

    Thanks for getting back so soon. A tutorial and useful Help files would make the app a lot more user friendly. Any thoughts on where to look for details, since the OP has come up short?
  • 5|=vv Level 3 Level 3 (685 points)
    baltwo wrote:
    ... I sort of understand the seed bit, but then how do you close the conditional and put in the actual equation? When I tried using x>3^x<9 3x+5 after the conditional, I kept getting the syntax error. </div>

    The 3x+5 phrase must be entered after clicking in the second seed which will have moved over to the right as you entered the expression for the first seed. Even though your insertion point will be just to the right of the second seed, you must click on the second seed (alternately you can press the right arrow key once to advance to the second seed) before entering the 3x+5.

    Thanks for getting back so soon. A tutorial and useful Help files would make the app a lot more user friendly. Any thoughts on where to look for details, since the OP has come up short?


    Its a shame that available documentation is so thin for Grapher. I think it has an incredible amount of depth to it, but it involves subtly and, in some cases, a strong mathematical background to realize its potential.
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