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Math Help - Quadratic Formula

  1. #1
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    Quadratic Formula

    Hi, I'm having a slight bit of trouble grasping the concept of the general quadratic formula, the part that involves surds.

    I have the question: Simplify 2+2 to the square root of 5 divided by 2.

    I also have a few other things i may need assistance on, but i'll start here.
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  2. #2
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    Re:

    Since you are dividing the two's both in the numerator and the denominator each of them cancel out and you are left with:
    Attached Thumbnails Attached Thumbnails Quadratic Formula-square-root.gif  
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    Quote Originally Posted by Kangarooo View Post
    Hi, I'm having a slight bit of trouble grasping the concept of the general quadratic formula, the part that involves surds.

    I have the question: Simplify 2+2 to the square root of 5 divided by 2.

    I also have a few other things i may need assistance on, but i'll start here.
    Is that 2 + 2^(sqrt(5)/2) ?

    If so, there's not much to simplify.

    2 + 2^(sqrt(5)/2) = 2(1 + 2^{(sqrt(5) - 2)/2})
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    qbkr21's interpretation works out nicer, so i'm guessing that's what the question should be. Please type your questions clearly, use brackets to show what belongs together, use / to show division and ^ to show powers
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    Quote Originally Posted by Kangarooo View Post
    Hi, I'm having a slight bit of trouble grasping the concept of the general quadratic formula, the part that involves surds.
    The quadratic formula is not a concept, it's just a formula. you just plug stuff into it to find the answer. the concept behind the quadratic formula is called completing the square, you will have to learn that method of solving quadratics as well.

    The quadratic formula says:

    Given a quadratic of the form
    ax^2 + bx + c = 0
    then the roots are given by the formula
    x = [-b +/- sqrt(b^2 - 4ac)]/2a

    so you just plug in the numbers in their respective positions.

    e.g. Solve 2x^2 + 5x + 1 = 0
    => x = [-5 +/- sqrt(25 - 4(2)(1)]/2*2 = [-5 +/- sqrt(17)]/4
    so x = [-5 + sqrt(17)]/4 or x = [-5 - sqrt(17)]/4

    Note: the roots of a function of x are the x values that cause the function to be zero. so once we have a quadratic = 0, solving for x gives the roots
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    Re:

    Re:
    Attached Thumbnails Attached Thumbnails Quadratic Formula-square-root-2.1.gif  
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  7. #7
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    Ahh, i think my meaning was misinterpreted.

    I mean by 2+2 to the square root of 5 divided by 2 as everything past the divide is the numerator, and the 2 is the dinominator

    qbkr21, how did you make that picture, i would be able to show you if i had that program
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    Quote Originally Posted by Kangarooo View Post
    Ahh, i think my meaning was misinterpreted.

    I mean by 2+2 to the square root of 5 divided by 2 as everything past the divide is the numerator, and the 2 is the dinominator

    qbkr21, how did you make that picture, i would be able to show you if i had that program
    Is this what you mean? The program we use here is called MathType
    Attached Thumbnails Attached Thumbnails Quadratic Formula-simplify.gif  
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  9. #9
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    Re:

    Jhevon recommended it to me. It is called MathType 5. I am now obsessed with it...
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  10. #10
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    Yes, thankyou all
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    Quote Originally Posted by Kangarooo View Post
    Yes, thankyou all
    Did you understand the process?
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    Re

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    Attached Thumbnails Attached Thumbnails Quadratic Formula-quadratic-example.gif  
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  13. #13
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    ah, wait, how does the second step of the quadratic formula work?

    This one:
    Attached Thumbnails Attached Thumbnails Quadratic Formula-equation.gif  
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    Quote Originally Posted by Kangarooo View Post
    ah, wait, how does the second step of the quadratic formula work?

    This one:
    you split it in two. one answer is with the plus sign, the other is with the minus sign

    so x = (4 + 2sqrt(10))/4 or x = (4 - sqrt(10))/4 ......and continue
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  15. #15
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    I use LaTeX.

    You can use the one they have on Wikipedia.
    Use <math></math> to type code.

    You can also use one they have on PlanetMath
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