Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
FibonacciMariachi
Group Title
Find a parametrization of the surface Σ.
Σ is the part of a cylinder x^2+y^2=1 that lies between the planes z=1 and z=1.
 2 years ago
 2 years ago
FibonacciMariachi Group Title
Find a parametrization of the surface Σ. Σ is the part of a cylinder x^2+y^2=1 that lies between the planes z=1 and z=1.
 2 years ago
 2 years ago

This Question is Closed

henpen Group TitleBest ResponseYou've already chosen the best response.1
dw:1352924458586:dw
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
I'm not sure what you mean by parametrise
 2 years ago

FibonacciMariachi Group TitleBest ResponseYou've already chosen the best response.0
Meaning put it into parametric form. <x,y,z>
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
OK. Forget about the z for a minute \[f(t)=cost \hat{x}+sint \hat{y} \] Is the circle
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
\[0 <t<2 \pi\]
 2 years ago

FibonacciMariachi Group TitleBest ResponseYou've already chosen the best response.0
Gotcha. Im mostly fine with finding. x=rcos(theta) y=rsin(theta). Im not sure how to find z though.
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
Now, to include the z coordinate:\[cost \hat{x}+sint \hat{x}+(\frac{t}{\pi}1)\hat{z}\] \[ 0<t<2 \pi \]I basically twisted the z thing to get something that linearly went from z=1 at t=0 to z=1 at t=2 pi
 2 years ago

FibonacciMariachi Group TitleBest ResponseYou've already chosen the best response.0
Hmmm, not 100% sure how you go to that point. Could you break it down for me?
 2 years ago

FibonacciMariachi Group TitleBest ResponseYou've already chosen the best response.0
Mainly, where did t/pi1 come from? And what goes into t? The z coordinate says the answer is simply 'zk'
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
Because \[t=0, (\frac{0}{\pi}1))=1\] \[t=0, (\frac{2 \pi}{\pi}1))=1\]
 2 years ago

FibonacciMariachi Group TitleBest ResponseYou've already chosen the best response.0
Hmmm I think I get it a little more now. :/ Still really murky on it though. the way I learned it was to just plug your parametrized x and y back into an equation with z in it and you find your z that way. Ehhh.
 2 years ago

FibonacciMariachi Group TitleBest ResponseYou've already chosen the best response.0
I really don't think I even understand the basic concept of this section to be honest.
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
It certainty doesn't help that I was incorrect. What I actually coded for wasdw:1352927439044:dw
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
That is, a spiral rather than a full curve
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
http://tutorial.math.lamar.edu/Classes/CalcIII/ParametricSurfaces.aspx There's cylinder in there. I'll explain if more help needed, sorry for mistake earlier
 2 years ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.