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Thread: Opinion on math questions

  1. #1
    I_royalty_I's Avatar
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    Opinion on math questions





    When you see something like the above examples, what would you think when you saw "6^-1" ? My professor took 60% off of both those questions because he said I had it in the incorrect format. So instead of grading my work and the correct answer, he graded me on formatting. Am I the only one who can understand that means 6 raised to the negative 1? Confused..
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  2. #2
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    I have always written it the same way that you do... Did your teacher actually tell you how he wanted it written or how he interpreted it? I'm confused about what else he expected you to do. @(you need an account to see links)
    Last edited by Cath; 06-27-2016 at 02:00 PM.

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    I_royalty_I (06-27-2016)

  4. #3

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    I'll check the answers in MATLAB but both solutions appear to be correct.

    Your second final answer may be a bit out of place (I would have taken 56.25/.25 and put it on a separate line) but other than that everything is fine. I agree with Cath, I would have probably typed it the same way.

    edit: to nitpick, -5^2 is not correct (this would be -25), it should be (-5)^2, but that is the only mistake I can find (your answer is still correct).

    edit 2: I noticed your professor has used the equation editor in word. Perhaps he expected you to also use the equation editor. As an engineering major we're always expected to use it for all our equations in the papers we write.
    Last edited by cost; 06-27-2016 at 02:22 PM.

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    I_royalty_I (06-27-2016)

  6. #4
    I_royalty_I's Avatar
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    That's another question I was curious about. So you're saying -5^2 is different than (-5)^2? I find that strange haha.

    He never said that we had to use the equation editor or anything like that. There were no specific instructions other than the instructions along with each question. I mean, it's basic algebra so I figured he'd grade on the actual content and answer instead of the format. That seems silly to me. I feel like most people would be able to follow my train of thought.
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    I... don't get your professor's logic ._.
    They mean the same thing
    6-1 = 6^-1
    So no... you're not the only one :/.

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    if you aren't required to use the equation editor then yeah i don't understand why your formatting is considered to be incorrect.

    (-5)^2 is (-5)(-5)=25 and -5^2 is -(5)(5) which is -25 (basically carry out the exponent and then add a negative at the end). It's just something you should memorize.

    your first answer should not have gotten any points off, second answer i'd take off a small amount, but 60% each problem, i don't understand that.

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    Aw, I feel frustrated for you :/ Unless your professor was super extremely obsessively clear about how he wants formatting to be done, it's ridiculous that he took off so many points when you did show your work and it's clear how you came to your answers.


    From my experience, math professors generally want you to always continue the stream of logic exclusively with equal signs, rather than solving one piece of the equation at a time, though (since you were essentially using substitution, in which case you should probably make it clear you were using substitution, like this

    (6^-1 - 9^-1)^-1 = (a - b)^-1 = (3/18 - 2/18)^-1 = (1/18)^-1 = 18

    a= 6^-1 = 1/6 = 3/18
    b = 9^-1 = 1/9 = 2/18

    It's likely your teacher wanted this though, in terms of format (notice every step follows linearly from the previously one with an equal sign):

    (6^-1 - 9^-1)^-1
    = (1/6 - 1/9)^-1
    = (3/18 - 2/18)^-1
    = (1/18)^-1
    = 18

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    Is our teacher old?

  11. #9



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    Quote Originally Posted by I_royalty_I View Post
    That's another question I was curious about. So you're saying -5^2 is different than (-5)^2? I find that strange haha.
    Yes, these two actually are different. The first means (-1)x5^2 whereas the second means (-5)^2, it doesn't change your answer all the time, but it will sometimes and that's why it can be an issue
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  12. #10
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    He is old, and apparently set in his ways.
    He told me the point is not only to get the right answer but also communicate correctly in mathematics. So I guess if I get the wrong answer but have the correct format I will get 60% of the points instead of the 40% I got now. Cool haha.

    He made us submit everything online instead of printing it out and turning in a hard copy. If I had been able to turn in a hard copy, I'd have gotten no points off because there would be no question about what is the exponent and what isn't. I got a 75% when I should have gotten 100% in my opinion. This guy x.x
    What's my definition of success?
    Creating something no one else can
    Being brave enough to dream big
    Grindin' when you're told to just quit
    Giving more when you got nothin' left

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