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
Explanation: