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AonZ
Group Title
Eliminate A from each pair of parametric equations
x = 3sinA
y= 6sin2A
 one year ago
 one year ago
AonZ Group Title
Eliminate A from each pair of parametric equations x = 3sinA y= 6sin2A
 one year ago
 one year ago

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dan815 Group TitleBest ResponseYou've already chosen the best response.0
dw:1369436912384:dw
 one year ago

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

AonZ Group TitleBest ResponseYou've already chosen the best response.0
its sin2A 2sinAcosA
 one year ago

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

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

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

genius12 Group TitleBest ResponseYou've already chosen the best response.1
Btw, 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
 one year ago

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

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

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

genius12 Group TitleBest 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
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
dw:1369437576413:dw
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
is that readable
 one year ago

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

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

genius12 Group TitleBest ResponseYou've already chosen the best response.1
Both @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.
 one year ago

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

dan815 Group TitleBest ResponseYou've already chosen the best response.0
dw:1369437924563:dw
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
dw:1369437958849:dw
 one year ago

genius12 Group TitleBest ResponseYou've already chosen the best response.1
Rearrange 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
 one year ago

genius12 Group TitleBest ResponseYou've already chosen the best response.1
I 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.
 one year ago

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

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

jdoe0001 Group TitleBest ResponseYou've already chosen the best response.0
right, so I notice
 one year ago

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

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

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

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

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

AonZ Group TitleBest ResponseYou've already chosen the best response.0
last question :)
 one year ago

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

AonZ Group TitleBest ResponseYou've already chosen the best response.0
got 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
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
dw:1369438736058:dw
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
2 ways to go from cosa to a/2 or other way, which trig u know
 one year ago

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

dan815 Group TitleBest ResponseYou've already chosen the best response.0
dw:1369439021400:dw
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
dw:1369439046456:dw
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
see if that helps
 one year ago

dan815 Group TitleBest ResponseYou've already chosen the best response.0
look at the formula for Cos(2a) and that tan^2a either one of those will help you simplify and eliminate a
 one year ago
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