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Thread: Hey, new here and looking for Math help!.

  1. #1 Hey, new here and looking for Math help!. 
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    Before I ask my question, I'm just wondering if it's ok to keep using this thread to ask any math questions I have from now, to the future rather than create a new topic every time?.

    My question that I'm struggling on is:

    Make the symbol indicated in square brackets the subject of each of the formula shown:

    m = (2(t-an)) / (n(n-1)) [a]

    *EDIT

    Here is my attempt:

    I used
    a = 4
    n = 2
    m = -5 (obtained from doing original equation)
    t = 3

    m = (2(3-4*2)) = -10 = -5
    2(2-1) = 2 =

    a = n(n-1) m = -10 = -5 once again
    2t -2a = 2

    ~Just isn't making sense.


    Last edited by MstrKurt; January 21st, 2013 at 10:28 PM.
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  3. #2  
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    Quote Originally Posted by MstrKurt View Post
    Before I ask my question, I'm just wondering if it's ok to keep using this thread to ask any math questions I have from now, to the future rather than create a new topic every time?
    By all means, please do that.
    Quote Originally Posted by MstrKurt View Post
    m = (2(t-an)) / (n(n-1)) [a]
    Could you use this link to present your work?
    Online LaTeX Equation Editor - create, integrate and download
    Make sure it's translated into phpbb format first, then copy and paste over here...


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  4. #3  
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    1. OK. First you're going the right way about asking for help. The basic rule for anyone is that you have to "show your working" if you want help. We will not give solutions or answers for homework or assignments as they are set. Only for the problems that people have with doing the work themselves.

    2. This problem. I don't know why you are substituting numerical values to solve this problem. That can be one way to check a solution to this problem, but if you want to get a alone on the left hand side, you have to manipulate the equation as given to get a all by it's lonesome using nothing more than what you started with.

    Have you done all the preliminary simpler versions of such exercises?
    Like these for instance.

    Make [x] the subject of the following formulae

    y = x + 4

    y = 5x

    a = b + 2x

    m = n - x/4

    p = (3 + 7x)/ 2

    s = (t + 4x)/ (v - 3)

    I found this looking for algebra exercises to work through. They should help.
    maths.com - Algebra - Changing The Subject Of A Formula
    "Courage is what it takes to stand up and speak; courage is also what it takes to sit down and listen." Winston Churchill
    "nature is like a game of Jenga; you never know which brick you pull out will cause the whole stack to collapse" Lucy Cooke
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  5. #4  
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    Hey thanks for the replies.

    I have done what you asked and converted the equation:


    The reason I put values in was to check whether I was going along the right lines to check my answer.

    From the list Adelady has supplied, I got the following results:

    y = x + 4 = y - 4 = x

    y = 5x = y / 5 = x

    a = b + 2x = (a - b) / 2 = x

    m = n - x/4 = (n - m) / 4 = x

    p = (3 + 7x)/ 2 = (2p - 3) / 7 = x

    s = (t + 4x)/ (v - 3) = (s(v - 3) - t) / 4 = x
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  6. #5  
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    If you were my student you'd be in deep, deep doo doo right now.

    Never, ever, ever put more than one = sign on a line. It's a sin.

    I know some people will tell me I'm a grumpy old lady, but until you're really fluent with this stuff you should write equations and solutions a line at a time. Makes it easier for tracking back when errors are obvious in the answer, or just to check on the steps when you're half way through a messy set of calculations. For my own students I insist that the = signs should all be in a vertical line. Makes it easy to see at a glance whether they're following the rules.

    Apart from that, you're getting the idea. I'd strongly suggest you work your way through the examples at that link I gave you. Especially the very first step of reversing the equation when the term you want to isolate is (somewhere) on the right hand side.
    "Courage is what it takes to stand up and speak; courage is also what it takes to sit down and listen." Winston Churchill
    "nature is like a game of Jenga; you never know which brick you pull out will cause the whole stack to collapse" Lucy Cooke
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  7. #6  
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    Ok, thank you for your help.. I'll give them a go
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  8. #7  
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    Quote Originally Posted by adelady View Post

    Never, ever, ever put more than one = sign on a line. It's a sin.


    Should I go to confession?
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    Quote Originally Posted by Guitarist View Post
    Quote Originally Posted by adelady View Post

    Never, ever, ever put more than one = sign on a line. It's a sin.


    Should I go to confession?
    Lol!
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    "In the four sided figure ABCD, AB = 6cm and AC = 7cm, angle BAC = 49 deg, angle ADC = 74 deg and angle DAC = 30 deg."

    There is no shape on the page to go by, how do I know what this shape looks like?.
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    Quote Originally Posted by MstrKurt View Post
    "In the four sided figure ABCD, AB = 6cm and AC = 7cm, angle BAC = 49 deg, angle ADC = 74 deg and angle DAC = 30 deg."

    There is no shape on the page to go by, how do I know what this shape looks like?.
    The way I'd do it is to start constructing it with a ruler and protractor. Draw line AD. You don't know how long it is yet. Then draw a line at 30 degrees to AD, 7 cm long. That's AC. Then just keep working with the information you are given.
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  12. #11  
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    Thank you for your reply .

    Another question: If I'm differentiating for example

    I know the Sq Rt becomes power 1/2 or as I prefer in decimal 0.5

    would that 0.5 then multiply the ^3?
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  13. #12  
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    Quote Originally Posted by MstrKurt View Post
    Thank you for your reply .

    Another question: If I'm differentiating for example

    I know the Sq Rt becomes power 1/2 or as I prefer in decimal 0.5

    would that 0.5 then multiply the ^3?
    OK, essentially what you want to know is whether

    Squaring both sides won't effect the equality, so the issue is whether

    On the left-hand side, the square simply kills off the square-root. On the right-hand-size



    by the definition of a square Edited: original erroneously said square root. It is
    that I used.

    and certainly



    So the multiplication of 3 by 0.5 is justified.

    If working in that direction seems a bit mysterious, just start with the obvious last line and work upwards to the first line. In either case, working it out yourself will help see what is happening.


    At the same time, I learned some tex.
    Last edited by mvb; January 24th, 2013 at 06:20 PM.
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    Quote Originally Posted by mvb View Post
    by the definition of a square root

    and certainly

    Definition of a cube root you mean?
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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  15. #14  
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    Quote Originally Posted by KALSTER View Post
    Quote Originally Posted by mvb View Post
    by the definition of a square root

    and certainly

    Definition of a cube root you mean?
    Actually I should have said the definition of a square: (t^n)^2 = t^(2n)
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