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In integration how much marks i will loose for not writing +c

  1. Apr 24, 2010 #1
    1) in my exams there were 3 simple questions on integration carrying 5 marks each, i solved them correctly but the only mistake i did was at the end of each step i didnt write "+c"

    like for example the final step of an integration problem is suppose say:
    x2+9x2+c

    so how much marks i will loose out of 5 for not writing that +c

    2) and for another question i wrote √50 instead of writing 5√2 as the answer, is that ok or i will loose marks for the same, meaning can 5√2 be also written as √50
     
  2. jcsd
  3. Apr 24, 2010 #2

    HallsofIvy

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    Do you not understand that each teacher has to decide that for him or herself? No one can tell how many marks another person might take off for a specific mistake.
     
  4. Apr 24, 2010 #3
    oh thanks

    but what about my second query i.e. can 5√2 be also written as √50, are both the things correct as far as an answer is concerned
     
  5. Apr 24, 2010 #4
    The more math a teacher knows, the less likely you are to get points off for this stuff. I could picture a middle school teacher taking points off for writing 3/2 instead of 1.5 or 1 1/2, or a high school algebra 1 teacher deducting points for your answer, but hopefully a calculus teacher will recognize that your answer is fine.

    You'd have a valid complaint if any points are deducted.
     
  6. Apr 24, 2010 #5

    Nabeshin

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    Agree. It's a calculus course, not a course in simplifying radicals.
     
  7. Apr 26, 2010 #6

    Mentallic

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    HallsofIvy's response was directed at both questions. The same reasoning applies.

    From my experience with forgetting +c is that you can hope to get 4/5. Depending on the teacher, either 1 point deducted for the first +c missing and then ignoring all others as "carry on" errors, or taking 1/2 off for each question. You can argue for more points if the teacher chooses this second approach. Something along the lines of "Of course, if I put +c in any one of them, I would've remembered to do that for all of them".
     
  8. Apr 26, 2010 #7
    Great. Will this site become a place to get ammunition to argue for partial credit with your instructor?
    [URL]http://www.cartoonstock.com/newscartoons/cartoonists/aba/lowres/aban76l.jpg[/URL]
     
    Last edited by a moderator: Apr 25, 2017
  9. Apr 26, 2010 #8
    X^2 + 9x^2 = 10x^2
     
  10. Apr 26, 2010 #9

    CompuChip

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    Long answer:*
    I think the simplification is more a matter of taste.
    Personally, I would say that √50 is at least just as good as 5√2 and would not deduct points for that, just like for writing ln(1/2). However, this is a thin line: when a student wrote down √49 or ln(1/e) I would definitely not give them full credit.

    In integration problems, also the context of the problem plays a part. Does the question ask for the or a primitive function? Is the integration the end goal of the exercise, or part of a larger question? Are there integration boundaries (like in: calculate the area under the graph)?


    *) Short answer: What Halls said
     
  11. Apr 26, 2010 #10
    I'd say that it depends on the problem.. If it was a more theoretical problem, the + C part has enough significance to lose some marks.. If it was more computational, I wouldn't deduct too many marks -- you did to most of the work. But anyway, I once lost enough marks for forgetting a '=' sign in a '<=' sign.. And I think that forgetting + C is worse.
     
  12. Apr 26, 2010 #11
    If the limits aren't there, you should add the plus C....
     
  13. May 18, 2010 #12
    not lost a single mark

    wow i have not lost a single mark for not writing that +c i got exactly 70 marks as i wanted, cant believe :surprised

    just reveled from the stress
     
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