Piecewise Position 5E2506
1. **State the problem:** We have a piecewise function for position $x(t)$ over time $t$ defined as:
$$x(t) = \begin{cases} 10t & 0 \leq t \leq 1 \\ -\frac{4}{3}t^2 + \frac{38}{3}t - \frac{4}{3} & 1 < t \leq 4 \\ 2t + 20 & 4 < t \leq 5 \end{cases}$$
We want to graph this function showing the position in meters over time in seconds.
2. **Explain the segments:**
- From $0$ to $1$ second, the position increases linearly with slope $10$.
- From $1$ to $4$ seconds, the position follows a quadratic curve.
- From $4$ to $5$ seconds, the position again changes linearly but with slope $2$ and intercept $20$.
3. **Plotting approach:**
- Plot each segment on its respective interval.
- Ensure continuity at the boundaries $t=1$ and $t=4$.
4. **Check continuity at $t=1$:**
- Left limit: $x(1) = 10 \times 1 = 10$
- Right limit: $x(1) = -\frac{4}{3}(1)^2 + \frac{38}{3}(1) - \frac{4}{3} = -\frac{4}{3} + \frac{38}{3} - \frac{4}{3} = \frac{30}{3} = 10$
5. **Check continuity at $t=4$:**
- Left limit: $x(4) = -\frac{4}{3}(16) + \frac{38}{3}(4) - \frac{4}{3} = -\frac{64}{3} + \frac{152}{3} - \frac{4}{3} = \frac{84}{3} = 28$
- Right limit: $x(4) = 2 \times 4 + 20 = 8 + 20 = 28$
6. **Final graph function:**
$$
y = \begin{cases} 10t & 0 \leq t \leq 1 \\ -\frac{4}{3}t^2 + \frac{38}{3}t - \frac{4}{3} & 1 < t \leq 4 \\ 2t + 20 & 4 < t \leq 5 \end{cases}
$$
This piecewise function can be graphed to show the position over time with smooth transitions at $t=1$ and $t=4$.
**Answer:** The graph consists of three segments as defined above, continuous at the joining points.