Lost in Calculus 3

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I am trying to understand Cal 3. So far I have done really well at 1&2. But I have a new professor for 3 and do not understand half of what we are doing. Is there any recomendations for resources to learn this material?
 
I'm sorry, but there is no fixed meaning for "Calc I", "Calc II", and "Calc III" (or, where I went to school, "Calc IV"); in particular, there is no canonical list of the topics that will be covered in courses having these names.

It would likely be helpful if you listed the topics with which you are having difficulty.

Thank you.

Eliz.
 
Sorry

I'm sorry sometimes I get used to relaying the name of the course alone. One thing that I ma not grasping is the squeeze theorum. There are other parts that I am not getting to well. This is the main one.Our book explains this differently than the professor. I dont know how to be more precise than this because I dont understand what I am doing.
 
I am surprised that you did not see the so-called ‘Squeeze Theorem’ in the calculus courses that you have already taken. It is such a basic principle.
This just reinforces what Eliz told you about the calculus sequence

Rather than have us guess, why not post a particular problem?
Tell us exactly what you do not understand.
Then we will try to help you.
 
Re: Sorry

Carter said:
I'm sorry sometimes I get used to relaying the name of the course alone.
Click to expand...
Don't worry 'bout it! Many students do the same thing, not having the background necessary to know about the lack of naming conventions. At least you didn't do what many grade-schoolers do: They'll say stuff like "I'm in Mrs. Adams' class at ABC Elementary, and I need help with what she did yesterday because I was out sick", like we would have any way of knowing. :wink: :D

Carter said:
One thing that I ma not grasping is the squeeze theorum.
Click to expand...
Do a search for "squeeze theorem", and another for "sandwich theorem". There may be other names for this, but I think those are the two "biggies". And, yes, use the quote-marks to narrow your search. You should quickly find some useful info.

Hope that helps!

Eliz.
 
Squeeze theorum

Thanks for the advise stapel. No we didnt see this prior to where I am now. I know that when I the details are explained I will probably be mad that I didnt see it already. Two problems that I have in front of me are: lim of (x,y) approaches (0,0) (2*x^2*y/x^4+y^2); and
lim of (x,y) approaches (0,0) (x^4-y^4/x^2+y^2)
I followed the one example that our instuctor did in class and for the second problem that I listed I got zero. By following him I may have worked completly wrong but it is about all I had to go by.
 
The first has nothing to do with the ‘Squeeze Theorem’.
It has to do with approaching (0,0) along different paths.
\(\displaystyle \L
\left\{ \begin{array}{l}
\mbox{along } y = x\quad \Rightarrow \quad \frac{{2x^3 }}{{x^4 + x^2 }} \to 0 \\
\mbox{along } y = x^2 \quad \Rightarrow \quad \frac{{2x^4 }}{{x^4 + x^4 }} \to 1 \\
\end{array} \right.\)

Therefore there is no limit! If there were a limit it would be path independent.

The second one is equally simple
\(\displaystyle \L
\frac{{x^4 - y^4 }}{{x^2 + y^2 }} = \frac{{\left( {x^2 - y^2 } \right)\left( {x^2 + y^2 } \right)}}{{x^2 + y^2 }} = \left( {x^2 - y^2 } \right)\quad \mbox{if}\quad xy \not= 0\)
 
Thanks

Thanks for the help. Getting strated always is the hardest for me. I keep working at it. Maybe next time I can find somrthing a little more challenging for you to help me with. Take care.
 
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