How to convert this parametric equation into a Cartesian equation?

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Sketch the curve by using the parametric equation to plot points. Indicate with arrow the direction in which the curve is traced as $t$ increases.



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




I tried to convert this parametric equation into a Cartesian equation, but I didn't know how. Please help.







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  • 1




    How did you try? What manipulations of it did you use? Did any of them get you a weird result? What have you found?
    – JMCF125
    Dec 27 '13 at 12:14






  • 1




    I don't think converting to Cartesian coordinates is what you were intended to do. Rather, select values of $t$ and then plot the points $(x,y)$ given by the parameterization. Then, informally deduce what the curve is. Note if you just look at the Cartesian equation, you won't be able to determine the direction in which the curve is traced out.
    – David Mitra
    Dec 27 '13 at 12:16











  • I have tried this x=t(t+1) and y=t(t-1), then t=y/(t-1)=x/(t+1) but I didn't know how to eliminate t
    – user32104
    Dec 27 '13 at 12:18










  • @DavidMitra thank you but how to know the shape without use points (because our teacher says we will not be able to draw table for points in the exam)
    – user32104
    Dec 27 '13 at 12:21










  • Well, the problem is oddly phrased then, it clearly indicates (to me at least) to use a "table method".
    – David Mitra
    Dec 27 '13 at 12:25














up vote
0
down vote

favorite













Sketch the curve by using the parametric equation to plot points. Indicate with arrow the direction in which the curve is traced as $t$ increases.



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




I tried to convert this parametric equation into a Cartesian equation, but I didn't know how. Please help.







share|cite|improve this question


















  • 1




    How did you try? What manipulations of it did you use? Did any of them get you a weird result? What have you found?
    – JMCF125
    Dec 27 '13 at 12:14






  • 1




    I don't think converting to Cartesian coordinates is what you were intended to do. Rather, select values of $t$ and then plot the points $(x,y)$ given by the parameterization. Then, informally deduce what the curve is. Note if you just look at the Cartesian equation, you won't be able to determine the direction in which the curve is traced out.
    – David Mitra
    Dec 27 '13 at 12:16











  • I have tried this x=t(t+1) and y=t(t-1), then t=y/(t-1)=x/(t+1) but I didn't know how to eliminate t
    – user32104
    Dec 27 '13 at 12:18










  • @DavidMitra thank you but how to know the shape without use points (because our teacher says we will not be able to draw table for points in the exam)
    – user32104
    Dec 27 '13 at 12:21










  • Well, the problem is oddly phrased then, it clearly indicates (to me at least) to use a "table method".
    – David Mitra
    Dec 27 '13 at 12:25












up vote
0
down vote

favorite









up vote
0
down vote

favorite












Sketch the curve by using the parametric equation to plot points. Indicate with arrow the direction in which the curve is traced as $t$ increases.



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




I tried to convert this parametric equation into a Cartesian equation, but I didn't know how. Please help.







share|cite|improve this question















Sketch the curve by using the parametric equation to plot points. Indicate with arrow the direction in which the curve is traced as $t$ increases.



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




I tried to convert this parametric equation into a Cartesian equation, but I didn't know how. Please help.









share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Aug 24 at 8:03









Rodrigo de Azevedo

12.7k41751




12.7k41751










asked Dec 27 '13 at 12:08









user32104

1972518




1972518







  • 1




    How did you try? What manipulations of it did you use? Did any of them get you a weird result? What have you found?
    – JMCF125
    Dec 27 '13 at 12:14






  • 1




    I don't think converting to Cartesian coordinates is what you were intended to do. Rather, select values of $t$ and then plot the points $(x,y)$ given by the parameterization. Then, informally deduce what the curve is. Note if you just look at the Cartesian equation, you won't be able to determine the direction in which the curve is traced out.
    – David Mitra
    Dec 27 '13 at 12:16











  • I have tried this x=t(t+1) and y=t(t-1), then t=y/(t-1)=x/(t+1) but I didn't know how to eliminate t
    – user32104
    Dec 27 '13 at 12:18










  • @DavidMitra thank you but how to know the shape without use points (because our teacher says we will not be able to draw table for points in the exam)
    – user32104
    Dec 27 '13 at 12:21










  • Well, the problem is oddly phrased then, it clearly indicates (to me at least) to use a "table method".
    – David Mitra
    Dec 27 '13 at 12:25












  • 1




    How did you try? What manipulations of it did you use? Did any of them get you a weird result? What have you found?
    – JMCF125
    Dec 27 '13 at 12:14






  • 1




    I don't think converting to Cartesian coordinates is what you were intended to do. Rather, select values of $t$ and then plot the points $(x,y)$ given by the parameterization. Then, informally deduce what the curve is. Note if you just look at the Cartesian equation, you won't be able to determine the direction in which the curve is traced out.
    – David Mitra
    Dec 27 '13 at 12:16











  • I have tried this x=t(t+1) and y=t(t-1), then t=y/(t-1)=x/(t+1) but I didn't know how to eliminate t
    – user32104
    Dec 27 '13 at 12:18










  • @DavidMitra thank you but how to know the shape without use points (because our teacher says we will not be able to draw table for points in the exam)
    – user32104
    Dec 27 '13 at 12:21










  • Well, the problem is oddly phrased then, it clearly indicates (to me at least) to use a "table method".
    – David Mitra
    Dec 27 '13 at 12:25







1




1




How did you try? What manipulations of it did you use? Did any of them get you a weird result? What have you found?
– JMCF125
Dec 27 '13 at 12:14




How did you try? What manipulations of it did you use? Did any of them get you a weird result? What have you found?
– JMCF125
Dec 27 '13 at 12:14




1




1




I don't think converting to Cartesian coordinates is what you were intended to do. Rather, select values of $t$ and then plot the points $(x,y)$ given by the parameterization. Then, informally deduce what the curve is. Note if you just look at the Cartesian equation, you won't be able to determine the direction in which the curve is traced out.
– David Mitra
Dec 27 '13 at 12:16





I don't think converting to Cartesian coordinates is what you were intended to do. Rather, select values of $t$ and then plot the points $(x,y)$ given by the parameterization. Then, informally deduce what the curve is. Note if you just look at the Cartesian equation, you won't be able to determine the direction in which the curve is traced out.
– David Mitra
Dec 27 '13 at 12:16













I have tried this x=t(t+1) and y=t(t-1), then t=y/(t-1)=x/(t+1) but I didn't know how to eliminate t
– user32104
Dec 27 '13 at 12:18




I have tried this x=t(t+1) and y=t(t-1), then t=y/(t-1)=x/(t+1) but I didn't know how to eliminate t
– user32104
Dec 27 '13 at 12:18












@DavidMitra thank you but how to know the shape without use points (because our teacher says we will not be able to draw table for points in the exam)
– user32104
Dec 27 '13 at 12:21




@DavidMitra thank you but how to know the shape without use points (because our teacher says we will not be able to draw table for points in the exam)
– user32104
Dec 27 '13 at 12:21












Well, the problem is oddly phrased then, it clearly indicates (to me at least) to use a "table method".
– David Mitra
Dec 27 '13 at 12:25




Well, the problem is oddly phrased then, it clearly indicates (to me at least) to use a "table method".
– David Mitra
Dec 27 '13 at 12:25










2 Answers
2






active

oldest

votes

















up vote
3
down vote













HINT:



On addition we have $displaystyle 2t^2=x+yiff t^2=fracx+y2$



On subtraction, $displaystyle 2t=x-yiff t=fracx-y2$



Can you eliminate $t$ from here?






share|cite|improve this answer
















  • 1




    Thank you, do you mean $((x-y)/2)^2=((x+y)2)$?
    – user32104
    Dec 27 '13 at 12:12







  • 1




    @user32104, my pleasure. Nice to hear that you could complete
    – lab bhattacharjee
    Dec 27 '13 at 14:44










  • how about x = 4 + 2t and y = 5 + 2t?
    – Hasan Iqbal
    Apr 4 '16 at 11:01

















up vote
2
down vote













HINT :
$t^2=x-t=y+t$.
So, you can represent $t$ by $x,y$.



Since we have $t=fracx-y2$, we have
$$x=left(fracx-y2right)^2+fracx-y2.$$



We can get the following equation with $x$ and $y$ :



$$x^2-2xy+y^2-2x-2y=0.$$






share|cite|improve this answer






















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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

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    up vote
    3
    down vote













    HINT:



    On addition we have $displaystyle 2t^2=x+yiff t^2=fracx+y2$



    On subtraction, $displaystyle 2t=x-yiff t=fracx-y2$



    Can you eliminate $t$ from here?






    share|cite|improve this answer
















    • 1




      Thank you, do you mean $((x-y)/2)^2=((x+y)2)$?
      – user32104
      Dec 27 '13 at 12:12







    • 1




      @user32104, my pleasure. Nice to hear that you could complete
      – lab bhattacharjee
      Dec 27 '13 at 14:44










    • how about x = 4 + 2t and y = 5 + 2t?
      – Hasan Iqbal
      Apr 4 '16 at 11:01














    up vote
    3
    down vote













    HINT:



    On addition we have $displaystyle 2t^2=x+yiff t^2=fracx+y2$



    On subtraction, $displaystyle 2t=x-yiff t=fracx-y2$



    Can you eliminate $t$ from here?






    share|cite|improve this answer
















    • 1




      Thank you, do you mean $((x-y)/2)^2=((x+y)2)$?
      – user32104
      Dec 27 '13 at 12:12







    • 1




      @user32104, my pleasure. Nice to hear that you could complete
      – lab bhattacharjee
      Dec 27 '13 at 14:44










    • how about x = 4 + 2t and y = 5 + 2t?
      – Hasan Iqbal
      Apr 4 '16 at 11:01












    up vote
    3
    down vote










    up vote
    3
    down vote









    HINT:



    On addition we have $displaystyle 2t^2=x+yiff t^2=fracx+y2$



    On subtraction, $displaystyle 2t=x-yiff t=fracx-y2$



    Can you eliminate $t$ from here?






    share|cite|improve this answer












    HINT:



    On addition we have $displaystyle 2t^2=x+yiff t^2=fracx+y2$



    On subtraction, $displaystyle 2t=x-yiff t=fracx-y2$



    Can you eliminate $t$ from here?







    share|cite|improve this answer












    share|cite|improve this answer



    share|cite|improve this answer










    answered Dec 27 '13 at 12:09









    lab bhattacharjee

    216k14153265




    216k14153265







    • 1




      Thank you, do you mean $((x-y)/2)^2=((x+y)2)$?
      – user32104
      Dec 27 '13 at 12:12







    • 1




      @user32104, my pleasure. Nice to hear that you could complete
      – lab bhattacharjee
      Dec 27 '13 at 14:44










    • how about x = 4 + 2t and y = 5 + 2t?
      – Hasan Iqbal
      Apr 4 '16 at 11:01












    • 1




      Thank you, do you mean $((x-y)/2)^2=((x+y)2)$?
      – user32104
      Dec 27 '13 at 12:12







    • 1




      @user32104, my pleasure. Nice to hear that you could complete
      – lab bhattacharjee
      Dec 27 '13 at 14:44










    • how about x = 4 + 2t and y = 5 + 2t?
      – Hasan Iqbal
      Apr 4 '16 at 11:01







    1




    1




    Thank you, do you mean $((x-y)/2)^2=((x+y)2)$?
    – user32104
    Dec 27 '13 at 12:12





    Thank you, do you mean $((x-y)/2)^2=((x+y)2)$?
    – user32104
    Dec 27 '13 at 12:12





    1




    1




    @user32104, my pleasure. Nice to hear that you could complete
    – lab bhattacharjee
    Dec 27 '13 at 14:44




    @user32104, my pleasure. Nice to hear that you could complete
    – lab bhattacharjee
    Dec 27 '13 at 14:44












    how about x = 4 + 2t and y = 5 + 2t?
    – Hasan Iqbal
    Apr 4 '16 at 11:01




    how about x = 4 + 2t and y = 5 + 2t?
    – Hasan Iqbal
    Apr 4 '16 at 11:01










    up vote
    2
    down vote













    HINT :
    $t^2=x-t=y+t$.
    So, you can represent $t$ by $x,y$.



    Since we have $t=fracx-y2$, we have
    $$x=left(fracx-y2right)^2+fracx-y2.$$



    We can get the following equation with $x$ and $y$ :



    $$x^2-2xy+y^2-2x-2y=0.$$






    share|cite|improve this answer


























      up vote
      2
      down vote













      HINT :
      $t^2=x-t=y+t$.
      So, you can represent $t$ by $x,y$.



      Since we have $t=fracx-y2$, we have
      $$x=left(fracx-y2right)^2+fracx-y2.$$



      We can get the following equation with $x$ and $y$ :



      $$x^2-2xy+y^2-2x-2y=0.$$






      share|cite|improve this answer
























        up vote
        2
        down vote










        up vote
        2
        down vote









        HINT :
        $t^2=x-t=y+t$.
        So, you can represent $t$ by $x,y$.



        Since we have $t=fracx-y2$, we have
        $$x=left(fracx-y2right)^2+fracx-y2.$$



        We can get the following equation with $x$ and $y$ :



        $$x^2-2xy+y^2-2x-2y=0.$$






        share|cite|improve this answer














        HINT :
        $t^2=x-t=y+t$.
        So, you can represent $t$ by $x,y$.



        Since we have $t=fracx-y2$, we have
        $$x=left(fracx-y2right)^2+fracx-y2.$$



        We can get the following equation with $x$ and $y$ :



        $$x^2-2xy+y^2-2x-2y=0.$$







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited Dec 28 '13 at 8:55

























        answered Dec 27 '13 at 12:09









        mathlove

        87.1k877208




        87.1k877208



























             

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