Eliminate the parameter to find a Cartesian equation of the curve.

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The discussion revolves around eliminating the parameter from the equations x = 1 - t² and y = t - 3 to derive a Cartesian equation for the curve. The user initially attempted to solve for t in terms of x but realized this approach only provided half of the parabola. They later discovered that solving for t in terms of y, leading to x = 1 - (y + 3)², yields the complete equation. The conversation emphasizes the importance of correctly manipulating the equations to capture the entire curve. Ultimately, the solution involves recognizing the need for both positive and negative roots to represent the full parabola.
Gundown64
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EDIT: Figured it out. Stupid me. I should have solved in terms of x, giving me x=1-(y+3)^2 as my answer.

Homework Statement


x= 1−t^{2}, y= t−3, −2 ≤ t ≤ 2

Eliminate the parameter to find a Cartesian equation of the curve for
−5 ≤ y ≤ −1

Homework Equations



N/A

The Attempt at a Solution



I solved for t and got \sqrt{1-x}. Then I plugged it into y=t-3 and got y=\sqrt{1-x}-3. However, that only gives me half of the parabola when I graph it. I know I need y=-\sqrt{1-x}-3 to get the other half, but how do I make that one equation. I don't think I can use a ± sign in my answer.

Thanks in advance!
 
Last edited:
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instead of solving t from x, try solving t from y and sub into x.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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