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Higher Maths (P1) Question 8(c)

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  • 06-06-2008 4:58pm
    #1
    Closed Accounts Posts: 17


    Ok there seems to be some debate as to the correct answer, so a simple post with your answer should help clear things up. BTW it was the Integration shaded area question.

    I got 19 units squared


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Comments

  • Closed Accounts Posts: 421 ✭✭Peslo


    Ok there seems to be some debate as to the correct answer, so a simple post with your answer should help clear things up. BTW it was the Integration shaded area question.

    I got 19 units squared


    Did anybody do what i did, and find the points of intersection, Then find the area enclosed by the curve and the line y=-5 and take away the area enclosed by the line and the line y=-5.
    The intervals where from -3 to 3.

    I realised at the end that there was another little bit to do, but only realised at the very end!!


  • Closed Accounts Posts: 21 NanoZoom555


    i got 99/8 units ^2 ,dont think its right tho,im hearing a lot of very different answers


  • Registered Users Posts: 2,904 ✭✭✭cian1500ww


    14 :(


  • Registered Users Posts: 17 Blackangel


    35/3 but i think its very wrong


  • Closed Accounts Posts: 122 ✭✭tramoredude


    I knew how to do it, but it looked so time consuming I just went onto Algebra, A girl in my class says she did it in "a minute or two" so she more than likely got the wrong answer too...

    I bet it would take 20 minutes to do it out properly! You had to subtract the area of the rectangle + the small triangle in the 4th quadrant too, anyone spot that? :p

    But over all it went well and I did a lot better than I thought I would


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  • Closed Accounts Posts: 259 ✭✭life_is_music


    yeah i did the rectangle/triangle thingy...

    Took me 4 pages to get it out

    I got 79/6 i think...... or maybe 77/6


  • Registered Users Posts: 1,583 ✭✭✭alan4cult


    Answer is 32/3 methinks


  • Closed Accounts Posts: 421 ✭✭Peslo


    Loads of people i know spent ages doin it, a few said it took 3 or 4 pages to do too


  • Registered Users Posts: 418 ✭✭Nanaki


    4/3 seems vveeeerrrry wrong!
    I got my limits (by plugging y=4-x^2 into the line, I think it was -1 and 3)
    Integrated the curve with the limits.
    Then did the line (realised halfway through - how the hell do ya intergrate y?!) and subtracted it from the curve.
    Kinda noticed that part of the area is below the x axis, does that have a bearing?

    Anyone want to post a worked solution?


  • Closed Accounts Posts: 773 ✭✭✭Cokehead Mother


    I'll LaTeX up a pretty solution - give me 5 minutes. :)


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  • Registered Users Posts: 22 Rich89


    Me and another guy i was talking to got 32/3


  • Registered Users Posts: 418 ✭✭Nanaki


    I'll LaTeX up a pretty solution - give me 5 minutes. :)

    excellent, thanks! :D


  • Registered Users Posts: 582 ✭✭✭TheAmateur


    Rich89 wrote: »
    Me and another guy i was talking to got 32/3
    If that means 10 and two thirds I think I got that too!


  • Registered Users Posts: 227 ✭✭jennyq


    Also 32/3, did it again just there to make sure.


  • Registered Users Posts: 309 ✭✭Decerto


    i just did it there and got 32/3 but in exam i used one wrong limit for very last bit under x axis in getting curve instead of 3 and 2 i used 3 and 1/2 anyone know what ill be docked for tht


  • Closed Accounts Posts: 773 ✭✭✭Cokehead Mother


    Turns out I lost the ability to LaTeX efficiently and correctly. As it transpires I have a (horrible) scanner. It's cut off at the end but the answer I have there is 32/3.

    epepg2.gif


  • Registered Users Posts: 252 ✭✭orangetictac


    Yup thats wat i got!


  • Closed Accounts Posts: 82 ✭✭hippety-pippety


    i got 9.... any takers?
    it took me a gud while bt 9 is a nice round number so i stuck with it rather than try agen.


  • Closed Accounts Posts: 5 shockingpinkdna


    I got 8. But then again I can't do Integration!


  • Registered Users Posts: 227 ✭✭delta214


    I got 32/3 also.
    I just moved my x axis down so that the point where the curve and line meet is on the axis. Made it much simpler i thought


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  • Registered Users Posts: 1,583 ✭✭✭alan4cult


    delta214 wrote: »
    I got 32/3 also.
    I just moved my x axis down so that the point where the curve and line meet is on the axis. Made it much simpler i thought
    How do you do that method?


  • Registered Users Posts: 55 ✭✭littlneutralone


    If you do it right but make stupid mental calculator mistakes is it only 3 marks you lose?

    Can't recall my answer. I think I did it the same way as posted above but 11.58am leaves little time for prudence.


  • Closed Accounts Posts: 773 ✭✭✭Cokehead Mother


    If you do it right but make stupid mental calculator mistakes is it only 3 marks you lose?

    Can't recall my answer. I think I did it the same way as posted above but 11.58am leaves little time for prudence.

    1 + 2 = 4 is a slip and you only lose 1 mark for them.


  • Closed Accounts Posts: 37 conor563


    I got 32/3. It took me ages! I got the area between the curve and the x-axis and the area between the line and the x-axis on both sides. Took the curve area from the positive area of the line and x-axis, then added that answer to the negative answer of the line and x-axis. Sorry if it sounds confusing, it very much is. Haven't a clue if its not the right answer!


  • Registered Users Posts: 589 ✭✭✭irish_boy90


    i got 6, looked up the method in my less stress more success.
    I got it wrong.

    wasn't too far off it though.
    didn't bother working out the real answer. P1 is over so I started on P2
    only looking to pass H irish and well I did a good oral. paper 2 is geting some much needed attention this weekend


  • Registered Users Posts: 392 ✭✭mrskinner


    if you want to move the 2 graphs up you add 5 to each,,,,

    y = 9 - x^2
    and
    y = 6 - 2x

    integrate the curve from -1 to 3 gives 26.666
    the area of the triangle is 12

    the difference is 14.6666 which is the shady area?


  • Closed Accounts Posts: 4 dyle123


    Glad to see many other people got 32/3 because that's what I got and so did another girl in my year!


  • Registered Users Posts: 55 ✭✭littlneutralone


    1 + 2 = 4 is a slip and you only lose 1 mark for them.
    Sweet. Hope they follow my method, it looked like a calculator regurgitated on the page. Actually if I'm hoping for stuff, I hope I got the answer.

    Anyway. Thanks.:pac:


  • Closed Accounts Posts: 59 ✭✭louise-x


    i can't even remember what i got, but looking at all this, it was wrong :(


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  • Registered Users Posts: 4,893 ✭✭✭Davidius


    That question looks big and scary to my poor 5th year brain. D:


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