A community for students.
Here's the question you clicked on:
 0 viewing
AonZ
 one year ago
Eliminate A from each pair of parametric equations
x = 3sinA
y= 6sin2A
AonZ
 one year ago
Eliminate A from each pair of parametric equations x = 3sinA y= 6sin2A

This Question is Closed

dan815
 one year ago
Best ResponseYou've already chosen the best response.0is it like that or is it sin^2A

jdoe0001
 one year ago
Best ResponseYou've already chosen the best response.0from x= 3sin(a), what would sin(a) be?

jdoe0001
 one year ago
Best ResponseYou've already chosen the best response.0.. right... ... is x= 3sin(a), what you have or x = 3cos(a)?

AonZ
 one year ago
Best ResponseYou've already chosen the best response.0the question is x = 3sinA

genius12
 one year ago
Best ResponseYou've already chosen the best response.1Btw, what do you mean by eliminate? Are you to convert this in to a rectangular equation with y in terms of x or are you to have both x and y written in terms of something else that isn't A? @AonZ

AonZ
 one year ago
Best ResponseYou've already chosen the best response.0write the equation simply without A

jdoe0001
 one year ago
Best ResponseYou've already chosen the best response.0@genius12 pretty much, is just conversion to rectangular

genius12
 one year ago
Best ResponseYou've already chosen the best response.1So y in terms of x and not A right?

genius12
 one year ago
Best ResponseYou've already chosen the best response.1\[\bf x=3\sin(A) \implies \frac{x}{3}=\sin(A) \implies \sin^{1} \left( \frac{x}{3}\right)=A\]Plug this value of A in y = 6sin(2A) and you're done. @AonZ

jdoe0001
 one year ago
Best ResponseYou've already chosen the best response.0dw:1369437887196:dw

dan815
 one year ago
Best ResponseYou've already chosen the best response.0well he shudnt get the asnwer too easily so its all good :)

genius12
 one year ago
Best ResponseYou've already chosen the best response.1Both @dan815 and mine rectangular forms work. Except his makes it more obvious that cosine and sine can be used parametrically to give an ellipse as dan's rectangular form is the equation of an ellipse.

AonZ
 one year ago
Best ResponseYou've already chosen the best response.0dw:1369437893899:dw i dont it get when u went into that part

genius12
 one year ago
Best ResponseYou've already chosen the best response.1Rearrange x and y so that:\[\bf \frac{y}{4x}=\cos(A) \ and \ \frac{x}{3}=\sin(A)\]Squaring both sides of both equations gives:\[\bf \left( \frac{y}{4x} \right)^2=\cos^2(A) \ and \ \left( \frac{x}{3} \right)^2=\sin^2(A)\]Adding both equations and using the identity cos^2(A) + sin^2(A) = 1 gives u the rectangular form. @AonZ

genius12
 one year ago
Best ResponseYou've already chosen the best response.1I just realised, @dan815 rectangular form actually won't be an ellipse even thought i looks like it will be lol. There is an x in the denominator under y which means it can't be the equation of an ellipse.

jdoe0001
 one year ago
Best ResponseYou've already chosen the best response.0not sure you can get rid of the "x" though, I got the same :S

dan815
 one year ago
Best ResponseYou've already chosen the best response.0u dont need to they just want an equation without A

AonZ
 one year ago
Best ResponseYou've already chosen the best response.0thank you so much :D understood @genius12 way much better

dan815
 one year ago
Best ResponseYou've already chosen the best response.0http://www.wolframalpha.com/input/?i=%28y%2F%284x%29%29%5E2%2B%28x%2F3%29%5E2%3D1

AonZ
 one year ago
Best ResponseYou've already chosen the best response.0was hard to read dan's writting :P

dan815
 one year ago
Best ResponseYou've already chosen the best response.0if u wanna see a nice graph :)

AonZ
 one year ago
Best ResponseYou've already chosen the best response.0can i pls get help on 1 more question? http://openstudy.com/study#/updates/519ff981e4b04449b221f091

jdoe0001
 one year ago
Best ResponseYou've already chosen the best response.0just post in the channel, so we can all see it and thus help :)

AonZ
 one year ago
Best ResponseYou've already chosen the best response.0got a link :P http://openstudy.com/study#/updates/519ff981e4b04449b221f091 but Question is Eliminate A from each pair of parametric equations x = 2tan( A/2) y = cosA

dan815
 one year ago
Best ResponseYou've already chosen the best response.02 ways to go from cosa to a/2 or other way, which trig u know

dan815
 one year ago
Best ResponseYou've already chosen the best response.0theres also an identity u can use straight from tan to a double angle

dan815
 one year ago
Best ResponseYou've already chosen the best response.0look at the formula for Cos(2a) and that tan^2a either one of those will help you simplify and eliminate a
Ask your own question
Sign UpFind more explanations on OpenStudy
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.