Monday 11 March 2013

Quadratic - Practice 6 (Ryan)



Practice 6, pg 156

7 comments:

  1. Real and distinct means that discriminant > 0 not =0
    Other than that the working is correct
    It is clear and easy to follow as he states the values of a, b and c
    Presentation is good as it clearly shows how he subs the values in

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  2. Neatness and organiztion: quite messy, took awhile to comprehend fully.
    Mathematical concepts: Why did you assume D = 0? You should just state that D has to be more than zero to be real and distinct. Other that that answer is okay.
    Explanation: Quite okay but should explain a bit more.

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  3. If the roots are real and distinct, the discriminant should be > 0, not equals to.
    The explanation is not clear or vivid as D = 0 at first but was then > 0 in the end. The presentation is thus rather messy as workings are not clear and concepts contradict each other.

    The presentation is sufficient.

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  4. Working is confusing because you introduce another variable a into the equation (in the line : a = a), so it might be unclear which "a" you are referring to

    At the last 2 lines, you wrote -20a > 0, then the equation suddenly turned into a < 0. THe explanation is not clearly stated and is unclear. you should explain how you arrived at the ans a is less than 0 even though your previous statement stated that -20a is more than zero

    Mathematical concept is prefectly fine and working is organised well.

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  5. The mathematical concept is incorrect. If the roots are real and distinct, the discriminant should be >0, and not D=0.
    The workings are unclear and a little messy and not very easy to follow.
    The answer answers to the question. However it is confusing as he stated that D=0, but ended off with D>0.

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  6. The organization is bad, a bit untidy and hard to follow.
    The explanation is well written but could be elaborated slightly more.
    A slight conception error. Real and distinct means discriminant must be more than 0 not equal to 0.
    Nicely shown the substitution.
    The answer correctly answers the question but a bit confusing.

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  7. Messy to start with but the presentation is well lay out despite making some concepts look contradictory. Some conceptual error

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