Substitude variables on a array of equations... - Hewlett Packard

This is a discussion on Substitude variables on a array of equations... - Hewlett Packard ; Hi all! I have a function that retuns me a array with two equations... Something like this: [x^2+y X^2-2y] Is there any way that i can use to substitute X and Y by real numbers, like; x=2 and y=1 And ...

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  1. Substitude variables on a array of equations...

    Hi all!

    I have a function that retuns me a array with two equations...
    Something like this:

    [x^2+y X^2-2y]

    Is there any way that i can use to substitute X and Y by real numbers,
    like;
    x=2 and y=1

    And get an array with the responses:
    [5 2]

    Thanks a lot!!!


  2. Re: Substitude variables on a array of equations...

    I'm not a big expert but I would use two mechanisms (in RPN):
    1) Give values to variabile (for aproximate result)
    [X^2+Y X2-2Y] using Matrix Writer (remember quote ' to input algebric
    construct)
    2
    'X'
    STO
    1
    'Y'
    STO
    ->NUM

    3) Use symbolic substitutions (SUBST command in ALG menu)
    [X^2+Y X2-2Y] using Matrix Writer
    'X=2'
    SUBST
    'Y=1'
    SUBST
    EXPAND

    There is a | (where) construct but I'm not very able in using it. Pheraps
    some newsgroup "gurus" can help us.

    MS


  3. Re: Substitude variables on a array of equations...

    On Apr 18, 10:12 am, Regis Daniel
    wrote:
    > Hi all!
    >
    > I have a function that retuns me a array with two equations...
    > Something like this:
    >
    > [x^2+y X^2-2y]
    >
    > Is there any way that i can use to substitute X and Y by real numbers,
    > like;
    > x=2 and y=1
    >
    > And get an array with the responses:
    > [5 2]
    >
    > Thanks a lot!!!


    HI!

    It's very simple.
    Create an array with the matrix writer [white button - O (between N
    and P)], then press [orange button O (between N and P] to create an
    equation within the array, then press x^2+y, ENTER. Then repeat for
    the next equation, then ENTER to place the array on the stack. Your
    matrix should look like this:
    [ 'x^2+y' 'x^2-2*y'] in level 1. Then start a new array (see above),
    start equation writer within the array and enter x=2 Enter, eq writer,
    y=1, ENTER ENTER.
    The stack will now show (if things were done right):
    2: ['x^2+y' 'x^2-2*y]
    1: [x=2 y=1]
    now press: orange-4 (the ALG menu), NXT (to go to page two), press
    SUBST, and voila! X and Y will be substituted with the appropriate
    values. You will have to edit each element and press EVAL to reduce,
    but minor point.

    Please note: I assume you are using a 50g. If you don't have one, I
    hope you will give serious consideration getting one.

    I hope this helps!


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