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Find the Cartesian equivalent to the parametric equation x(t)= 3-2t and y(t)=(t^2) -2t

 Sep 1, 2016

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 #1
avatar+26393 
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Find the Cartesian equivalent to the parametric equation x(t)= 3-2t and y(t)=(t^2) -2t

 

\(\begin{array}{|rcll|} \hline x(t)&=& 3-2t \\ x-3 &=& 2t \\ \mathbf{2t} &\mathbf{=}& \mathbf{ x-3 }\\ \mathbf{t} &\mathbf{=}& \mathbf{\frac12 (x-3) } \\ \hline \end{array} \)

 

\(\begin{array}{|rcll|} \hline y(t)&=&(t^2) -2t \qquad &| \qquad \mathbf{t =\frac12 (x-3) } \\ y &=&[ \frac12 (x-3) ]^2 -(2t) \qquad &| \qquad \mathbf{2t = x-3 }\\ y &=&[ \frac12 (x-3) ]^2 -(x-3) \\ y &=&\frac14 (x-3)^2 -(x-3) \\ y &=&\frac14 (x-3)^2 -(x-3)\cdot \frac44 \\ y &=&\frac14 (x-3)\cdot [(x-3)-4] \\ y &=&\frac14 (x-3)\cdot [ x-3 -4] \\ y &=&\frac14 (x-3)\cdot ( x-7 ) \\ y &=&\frac14 (x^2-7x-3x+21) \\ \mathbf{y} &\mathbf{=}&\mathbf{ \frac14 \cdot (x^2-10x+21) }\\ \hline \end{array}\)

 

laugh

 Sep 2, 2016
 #1
avatar+26393 
+10
Best Answer

Find the Cartesian equivalent to the parametric equation x(t)= 3-2t and y(t)=(t^2) -2t

 

\(\begin{array}{|rcll|} \hline x(t)&=& 3-2t \\ x-3 &=& 2t \\ \mathbf{2t} &\mathbf{=}& \mathbf{ x-3 }\\ \mathbf{t} &\mathbf{=}& \mathbf{\frac12 (x-3) } \\ \hline \end{array} \)

 

\(\begin{array}{|rcll|} \hline y(t)&=&(t^2) -2t \qquad &| \qquad \mathbf{t =\frac12 (x-3) } \\ y &=&[ \frac12 (x-3) ]^2 -(2t) \qquad &| \qquad \mathbf{2t = x-3 }\\ y &=&[ \frac12 (x-3) ]^2 -(x-3) \\ y &=&\frac14 (x-3)^2 -(x-3) \\ y &=&\frac14 (x-3)^2 -(x-3)\cdot \frac44 \\ y &=&\frac14 (x-3)\cdot [(x-3)-4] \\ y &=&\frac14 (x-3)\cdot [ x-3 -4] \\ y &=&\frac14 (x-3)\cdot ( x-7 ) \\ y &=&\frac14 (x^2-7x-3x+21) \\ \mathbf{y} &\mathbf{=}&\mathbf{ \frac14 \cdot (x^2-10x+21) }\\ \hline \end{array}\)

 

laugh

heureka Sep 2, 2016

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