Can someone please explain it to me ASAP???!!! This is exponential model. What is doubling time is supposed to be ???

savings account advertises an annual percentage yield (APY) of 5.6%, which means that the balance in the account increases at an annual growth rate of 5.6%/ a. Find the balance in the account for t2 0 with an initial deposit of $2000 assuming the APY remains fixed and no additional deposits or withdrawals are made. b. What is the doubling time of the balance? c. After how many years does the balance reach $4500. a. Use the exact value of k when finding the balance in the account. The balance in the account is y(t) = 2000 e tin (1.056) (Type an expression using t as the variable.) b. The doubling time is 11.1 years. (Do not round until the final answer. Then round to the nearest tenth as needed.)