Is this a typo? - Integral of fraction

  • #1
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Part (1) of this question posted in post 3. Is it a type-o or correct. Not looking for solution.
 
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Answers and Replies

  • #2
Doug Huffman
Gold Member
804
111
Yes, it appears to be so, from what I can see.
 
  • #5
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What is a type-o? Or do you think it is a typo? Then type-o probably is a typo.
The integrals look ok so far.
 
  • #6
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Hint for part i): Try to rearrange ##6x^2-5x+3## into some polynome your can divide by ##12x-5## plus a constant.
 
  • #7
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Ya I differentiated the top and you get 12x-5 all over 12x-5.
 
  • #8
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Ah I see. Could be a typo. But this integral should be solvable as well.
 
  • #9
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Part 1&2 only worth 4% on exam paper. Seem like a but of work for 2%
 
  • #10
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Part 1&2 only worth 4% on exam paper. Seem like a but of work for 2%
Private theories are not allowed in this forum. :D But don't worry here. Sorry, I can only look at the math.
 
  • #11
34,675
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Anthonyk, why would you think the problem has a typo? This is an easy integral - just divide the numerator by the denominator.
 
  • #12
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Lecturer thinks it is because of the low mark. Looking back a previous exam papers made an assumption. If We are wrong I hold my hand up.
 
  • #13
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Anthonyk, why would you think the problem has a typo? This is an easy integral - just divide the numerator by the denominator.
That's are far as I got I had x-1.
 
  • #15
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Ya silly mistake by me.
 
  • #16
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ImageUploadedByPhysics Forums1428103350.262848.jpg


Wondering the the solution the this question is right or wrong ?
Thanks
 
  • #17
35,258
11,510
What happened in (4)? The denominators vanished?
Also, what happens if you differentiate your result? Do you get the initial fraction? This is often a very easy check you can always do if you are unsure.

The whole substitution is not helpful here. Posts 6 and 11 show the best approach.
 
  • #18
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This solution is from class. We were given a reason why that were moved but I can remember.
When studying on my own I divided the polynomial but the devision didn't look right. I'll attempt it again and post later. Thanks.
 
  • #21
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@anthonyk2013, once you've made it past grade school arithmetic, it's not a good idea to write fractions as mixed numbers (such as you have in your work). Instead of ##1 \frac 1 {24}## or ##1 \frac {23} {24}##, you really should write these as improper fractions, 25/24 and 47/24. Mixed numbers such as the ones you wrote are much harder to work with and can easily be confused if not written very carefully.
 
  • #22
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Ill finish later. Too many kids around[emoji86]
 
  • #23
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Thanks for the reminder mark44. Long time since i was in grade school as you call it
 
  • #24
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ImageUploadedByPhysics Forums1428239530.213025.jpg


Latest attempt. Wondered if I'm right.
 
  • #25
35,258
11,510
Integrating x/2 gave x2/2?
And check what you have in the denominators and logs - but I guess those are just typos.
 

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