Answer:
a) 1.5cm
b) dr/dt = 0.4cm/sec
Step-by-step explanation:
r = 0.4t + 1.5
Initial is at t = 0,
r = 1.5 cm
b)
dr/dt = 0.4cm/sec
Slope = change in r/change in t
0.4 is the rate of change in r with respect to time
Alternately,
At t = 0, r = 1.5
At t = 1, r = (0.4)(1) + 1.5 = 1.9
(1.9-1.5)/(1-0) = change in r/change in time
= 0.4 cm/sec
