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# Difficult Parametric Equation watch

1. Hey guys Can someone help me resolve the parametric equation I just find it practically impossible

x=t^2+t
y+t^2-t

I always seem to be having an extra t and I can't get rid of it what so ever.
2. (Original post by ChemBoy1)
Hey guys Can someone help me resolve the parametric equation I just find it practically impossible

x=t^2+t
y+t^2-t

I always seem to be having an extra t and I can't get rid of it what so ever.
Have u written the second one correctly?
3. if x = t2 + t

y = t2 - t

if you subtract them you can find an expressions for t involving x and y. then put this back into either of the two wherever it says t.
4. Sorry, I don't quite follow, if I subtract y -x I will get -2t. What should I do from there, the question wants me to plot it, and I we can't use graphical calculator, so If I could convert it into a Cartesian one, I could just put out a table of values.
(Original post by the bear)
if x = t2 + t

y = t2 - t

if you subtract them you can find an expressions for t involving x and y. then put this back into either of the two wherever it says t.
5. (Original post by ChemBoy1)
Sorry, I don't quite follow, if I subtract y -x I will get -2t. What should I do from there, the question wants me to plot it, and I we can't use graphical calculator, so If I could convert it into a Cartesian one, I could just put out a table of values.
you could choose values of t and work out x and y for each value ?
6. I presume you mean:

-

- =

(where the bold is my correction),

as you could find "x+y" and "x-y" to find terms with "t".
Then try to link expressions involving "x+y" and "x-y" together.

----------------------------------------------------------------------------------------

If you just need to plot a graph, then as "thebear" suggested, why not just pick values of t to find x and y?

Also, the cartesian form does not appear simple enough for simple plotting anyway.

Spoiler:
Show

A parabola rotated and shifted?

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Updated: October 28, 2017
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