Solved

Vector Calculus: Describing the graph of an equation

Posted on 2011-09-19
5
462 Views
Last Modified: 2012-06-27
Describe the graph of the equation:

r = 3cos(t) i + 2sin(t) j - k



I figured it out to be a elliptic cylinder in 3-space, but apparently it's not right? I was reading my book and it said something about being a helix but it does a terrible job explaining how it came to that conclusion. Any help is appreciated.
0
Comment
Question by:Zenoture
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
5 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 36564437
do you mean

r = 3cos(t) i + 2sin(t) j - k*t
0
 

Author Comment

by:Zenoture
ID: 36564454
nope, -k, i.e. z = -1
0
 
LVL 84

Accepted Solution

by:
ozo earned 250 total points
ID: 36564469
In that case, it seems like just an ellipse.
0
 

Author Comment

by:Zenoture
ID: 36564540
Yeah, on the plane z = -1

But how do I sketch that so it actually looks like it should? I'm terrible at drawing...
0
 
LVL 27

Assisted Solution

by:aburr
aburr earned 250 total points
ID: 36564935
"But how do I sketch that so it actually looks like it should?"
by putting a t in front of the k as ozo suggested.
Forget the k part for starters. What do you have? You have the end of the vector tracing out an ellipse.
Now put in the -K (unit vector in the z direction) What do you have? The ellipse drawn at -1 in the z direction.
That is not a helix.
Correct the misprint as ozo suggested. What do you now have? You have the point of the vector still going in its ellipse but now it is sinking steadily in the - z direction yielding the required helix.
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

A Guide to the PMT, FV, IPMT and PPMT Functions In MS Excel we have the PMT, FV, IPMT and PPMT functions, which do a fantastic job for interest rate calculations.  But what if you don't have Excel ? This article is for programmers looking to re…
Complex Numbers are funny things.  Many people have a basic understanding of them, some a more advanced.  The confusion usually arises when that pesky i (or j for Electrical Engineers) appears and understanding the meaning of a square root of a nega…
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question