Find the value of the line integral ?

C

CalleighMay

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Hey guys! I have been on the forum for about a week or so and have compiled a lot of information and techniques to help me understand calculus, so i really appreciate everyone's help!

I am a soon-to-be freshman in college and am taking a summer class, calculus II (took calc I in HS). This is our last week of class after our final exam so my professor is taking this time to give us a preview of what we will be learning in the fall semester in Calc III (since this is the same professor). Every Tuesday class our professor gives us a few problems from future sections and asks us to "see what we can come up with" and to work together to find solutions. The following Tuesday he asks us to discuss the problems as a class, seeing which ones of us know our stuff =P

Basically, i want to ask you guys what you think about these problems as i do them along before i have my discussion. I really want to make a lasting impression on my professor by "knowing my stuff" -to show him i can do it! All's i need is a little help! Would you guys mind giving me some help?

We are using the textbook Calculus 8th edition by Larson, Hostetler and Edwards and the problems come from the book.

The problem is on pg 1087 in chapter 15.3 in the text, number 16a and 16b ONLY. It reads:

Find the value of the line integral integral (with a C at the bottom) of F (with a dot) dr.
Then it gives integral (with c at bottom) of (2x-3y+1)dx -(3x+y-5)dy
For a) it gives a graph with the vertices's: (0,0), (4,1) and (2,3) and there is a label (c1) in the graph on the line from (0,0) to (2,3)
For b) it gives another graph with the vertices's: (0,1), (0,-1) and it gives a half-circle with an equation x=sqrt(1-y^2) and a label (C2) in the graph.

There are graphs C and D but he told us to only try a and b... If you have a copy of the book calculus 8th edition you can see the problem for yourself... if you think it's confusing here, you can only imagine how confusing it is to me lol =(

I did look at the solutions to the other odd (i cannot find answers to even ones) problems in this problem set but it's no use, i'm totally lost. He said this will eventually be important so i want to learn it now! lol

Can you guys help me? Thank you!!!!! :D
 
Is this a conservative vector field?.

Since \(\displaystyle \frac{{\partial}M}{{\partial}y}=\frac{{\partial}N}{{\partial}x}=-3, \;\ F(x,y)=(2x-3y+1)i-(3x+y-5)j\) is conservative.

The potential function is \(\displaystyle f(x,y)=x^{2}-3xy-\frac{y^{2}}{2}+x+5y+k\)
 
Oh gosh i haven't the slightest clue, i don't even understand the question in the book. Maybe if someone else has the book they can help me interpret what it's asking? =/
 
CalleighMay said:
duplicate post:

http://www.scienceforums.net/forum/show ... post427829


Oh gosh i haven't the slightest clue, i don't even understand the question in the book.

This is one of the better written books in the field. You are not spending enough time looking at the example problems.

I have a second edition of the book and in there, one of the example problems (example 5 p 788) describes lucidly - what does conservative force field mean. Use the index pages to find definitions and examples.

Maybe if someone else has the book they can help me interpret what it's asking? =/
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I understand that, but i was asking if there is a simpler way to understand the basics (aka with you guys' help) before i look for "what might be usefull" in this huge book lol. If the book was the easiest way to teach a student, there would be no teachers.
 
CalleighMay said:
I understand that, but i was asking if there is a simpler way to understand the basics (aka with you guys' help) before i look for "what might be usefull" in this huge book lol. If the book was the easiest way to teach a student, there would be no teachers.
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I'm sorry, but I don't know of any other way of saying what we've been saying:

To learn this material, you need to spend hours (days? weeks?) in self-study, which involves much more than a glance through the book for an example of "the exact same thing". You need to actually read the text (and other texts, for another "spin" or "angle" on the material), work through all of the examples until you can do them on your own (understanding how and why they work as they do), and learn the underlying concepts, terms, and techniques. Otherwise, you'll need to enroll in an appropriate course.

To repeat ourselves yet again, we cannot teach your next semester's course in this environment. There are valid reasons that your next course is going to take many chapters of a very large book and the many weeks of an entire semester, and one of those reasons is that the material cannot be "taught" in a dozen or so quickie forum posts.

Thus far, you have not, to all appearances, actually read the book that you already have, nor have you studied the replies you have received, even when you have been given the complete worked solution. (You have not generally seemed to have been aware of the fact that the answer had, in fact, been provided to you, evidenced by your replying by asking "So whats the ans LOL", etc.)

If we can see what is going on, do you really think your professor is going to fall for this? Do you really have that little respect for him? Surely not.

I would therefore respectfully request that, before replying again, you please make at least some token effort toward learning the material, so that you can respond intelligently, asking about the actual concepts and material, rather than merely making sure that the answers have been included for you to copy down as "your" "impressive" work.

Thank you.

Eliz.
 
i know you cannot teach it to me in such short time, nor can i learn it by myself in such short time either. I am merely asking for the solutions so i can have something to present, and to have something i can follow within the next few weeks so i can learn it. I promise you, you will never have to hear from me again after this... =/
 
I do not believe there is anyone who wishes never to hear from you again. The point you are not getting is that "the answer" is of very limited importance at this (and most other) levels of mathematics. If you have only the answer, you have almost nothing. If I were your math teacher, and you presented a bunch of answers that you did not understand, I would be 100% unimpressed. I might write on your paper, "So, did you learn anything? I can't tell." Your efforts that we have seen are just not worthwhile. Whatever utility you expect to gain from this exercise, as you have defined it, simply will evaporate.

My views. I welcome others'.
 
Hey guys, can someone give me the full solution please? We had class last night and he didn't really explain them but i would like to know the answers.

Thanks!
 
CalleighMay said:
Hey guys, can someone give me the full solution please? We had class last night and he didn't really explain them but i would like to know the answers.

Thanks!
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You have to show us that you are at least trying - and are capable of attending these classes that teach at this level.

The copy of the book that I have (2 nd edition) has very good example problems - almost exactly like the problem posted - I would assume 8 th edition will have similar/same example problems.

Read through those - copy one of those problems onto these pages to show that you are at least looking at those - then I would work with you....
 
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