Sketch. \bold{r}(t) = (t + 1)\bold{i} + (t^2 - 2)\bold{\bold{j}}
logistic_guy Senior Member Joined Apr 17, 2024 Messages 1,786 Jul 6, 2025 #1 Sketch. r(t)=(t+1)i+(t2−2)j\displaystyle \bold{r}(t) = (t + 1)\bold{i} + (t^2 - 2)\bold{\bold{j}}r(t)=(t+1)i+(t2−2)j
Sketch. r(t)=(t+1)i+(t2−2)j\displaystyle \bold{r}(t) = (t + 1)\bold{i} + (t^2 - 2)\bold{\bold{j}}r(t)=(t+1)i+(t2−2)j
logistic_guy Senior Member Joined Apr 17, 2024 Messages 1,786 Jul 6, 2025 #2 We can write this curve in terms of x\displaystyle xx and y\displaystyle yy if we are smart enough. Then, it is a piece of cake to recognize its graph! x=t+1\displaystyle x = t + 1x=t+1 This means: t=x−1\displaystyle t = x - 1t=x−1 This gives: y=t2−2=(x−1)2−2\displaystyle y = t^2 - 2 = (x - 1)^2 - 2y=t2−2=(x−1)2−2 This is just the graph of a parabola that is shifted one unit to the right and two units downward and concaves upward with its vertex at (1,−2)\displaystyle (1,-2)(1,−2) Since this is a parametrized curve, we expect it contains a path. It should be counterclockwise in this case. Why? Think about it!
We can write this curve in terms of x\displaystyle xx and y\displaystyle yy if we are smart enough. Then, it is a piece of cake to recognize its graph! x=t+1\displaystyle x = t + 1x=t+1 This means: t=x−1\displaystyle t = x - 1t=x−1 This gives: y=t2−2=(x−1)2−2\displaystyle y = t^2 - 2 = (x - 1)^2 - 2y=t2−2=(x−1)2−2 This is just the graph of a parabola that is shifted one unit to the right and two units downward and concaves upward with its vertex at (1,−2)\displaystyle (1,-2)(1,−2) Since this is a parametrized curve, we expect it contains a path. It should be counterclockwise in this case. Why? Think about it!