In an experiment, a biologist introduces a toxin into a bacterial colony and then measures the effect on the population of the colony. Suppose that at time t(in minutes) the population is given by P(t) = 31 + (30t^2 +4t+1)/(1-5t^2) + 20e^(-.04t)(t+1) measured in thousands. What will the population be as t approaches infinity (measured in thousands)?

I think this is a Series problem, help needed.

Thanks in advance