Answer:
An interesting experiment is given. We need to address various questions based on our knowledge of calculus.
Step 2
Part (a)
Time taken for the radius to grow to 2 cm = t1 = r/0.5 = 2/0.5 = 4 hours
Time taken for the radius to become 0 = t2 and the same can be obtained by solving:
r = 2 - √t2 = 0
Hence, t2 = 22 = 4 hours
Hence, the time duration of the entire experiment (from the introduction of the bacteria until its disappearance) = t1 + t2 = 4 + 4 = 8 hours
Step 3
Part (b)
r(t) = 0.5t for 0 ≤ t ≤ 4
and
r(t) = 2 - √(t - 4) for t > 2
Step-by-step explanation:
Answer:
Step-by-step explanation:

Answer:
2½ h
Step-by-step explanation:
Assume the graph is like the one below.
The graph shows how Erin's distance varies with time.
To find out how long it takes Erin to cover 25 mi, find 25 mi on the vertical axis.
From there, draw a horizontal line until it hits the graph.
Then drop a vertical line to the horizontal axis.
It hits half-way between 2 and 3.
It takes Erin 2½ h to run 25 mi.