AP Precalculus / Unit 4: Functions Involving Parameters, Vectors, and Matrices
4.2 Parametric Functions Modeling Planar Motion
Notes
$x(t)$ is horizontal position, $y(t)$ is vertical position. Together they show where an object is and which way it moves.
- If $x(t)$ is increasing, the object moves right. If $y(t)$ is increasing, it moves up.
Practice
$x(t)=5-t$. As $t$ increases, the object moves:
$x$ decreases.
A ball: $x(t)=10t$, $y(t)=-5t^2+20t$. Its height at $t=1$:
$-5+20$.
For that ball, when is it back at height 0 (after $t=0$)?
$-5t(t-4)=0$.
Ready for more? Take the Unit 4 test.