Final answer:
The fish population is changing at a rate of -47.2 fish per month at the end of 4 months.
Step-by-step explanation:
To find the rate at which the fish population is changing at the end of 4 months, we can use the derivative of the logistic function p(t). The derivative represents the rate of change of the population with respect to time. In this case, we need to find the derivative of p(t) and then substitute t=4.
We calculate the derivative using the chain rule:
p'(t) = (10,000/((1+19e^(-t/5))^2)) * (-(19/5)*e^(-t/5))
Now we substitute t=4 into the derivative:
p'(4) = (10,000/((1+19e^(-4/5))^2)) * (-(19/5)*e^(-4/5))
Calculating the numerical value of p'(4), we get approximately -47.2. So, the fish population is changing at a rate of -47.2 fish per month at the end of 4 months.