Answer:
dT/dt = k(L-Lt)
Step-by-step explanation:
Let the rate of growth in length be dL/dt
The difference between the current length L and the asymptotic length Lt will be expressed as L-Lt
If the rate of growth in length of an individual fish is proportional to the difference between the current length L and the asymptotic length Lt, this is expressed as;
dT/dt ∝ L-Lt
dT/dt = k(L-Lt) where
k is the proportionality constant
Hence the differential equation that expresses this idea is written as;
dT/dt = k(L-Lt)