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# Parametric equations watch

1. Hey I would like some help with these questions.

1.) x=t/(2t-1) y=t/(t+3)
2.) x=sin2theta y=costheta.
3.)x=sintheta +2costheta y=2sintheta +costheta

For all I need to find the Cartesian form. For the first one I got it down to y=x/(7x-3) and for the second one I got it to be x^2=y^2(4-4y^2). As for the third one I have no answer
2. (Original post by Sylarus)
Hey I would like some help with these questions.

1.) x=t/(2t-1) y=t/(t+3)
2.) x=sin2theta y=costheta.
3.)x=sintheta +2costheta y=2sintheta +costheta

For all I need to find the Cartesian form. For the first one I got it down to y=x/(7x-3) and for the second one I got it to be x^2=y^2(4-4y^2). As for the third one I have no answer
I got the same answer as you for the first and second, I'd reckon those answers are just fine.
For 3, remember that the sinx/cosx = tanx and you can eliminate sin and cos at the same time!
3. (Original post by Sylarus)
Hey I would like some help with these questions.

1.) x=t/(2t-1) y=t/(t+3)
2.) x=sin2theta y=costheta.
3.)x=sintheta +2costheta y=2sintheta +costheta

For all I need to find the Cartesian form. For the first one I got it down to y=x/(7x-3) and for the second one I got it to be x^2=y^2(4-4y^2). As for the third one I have no answer
Why don't you get and in terms of and then use ?
4. x = sinΘ + 2cosΘ

y = 2sinΘ + cosΘ

see what happens with squaring
5. I think this is a duplicate thread - looks awfully familiar.
6. (Original post by ghostwalker)
I think this is a duplicate thread - looks awfully familiar.
I was wondering that, I saw you and notnek answer something similar yesterday(?) but I wasn't sure, so I went ahead and replied to it anyway.

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