Agraphing calculator is recommended.

the rabbit population on a small island is observed to be given by the function
p(t) = 140t − 0.5t^4 + 1500
where t is the time (in months) since observations of the island began.

(a) when is the maximum population attained (round your answer to one decimal place.)
months

what is the maximum population? (round your answer to the nearest whole number.)
rabbits

(b) when does the rabbit population disappear from the island? (round your answer to one decimal place.)
months