$380 is invested in an account earning 8.9% interest (APR), compounded quarterly. Write a function showing the value of the account after tt years, where the annual growth rate can be found from a constant in the function. Round all coefficients in the function to four decimal places. Also, determine the percentage of growth per year (APY), to the nearest hundredth of a percent.
Compunded quarterly means 8.9% / 4 interest per quarter ...but you need it in DECIMAL form .089/4 = .0225 interest per period (quarter)
then the formula is
FV = PV (1+i)4t FV is FUTURE value PV = PRESENT value ($380) i is the periodic interest calculated above t is years....multiplied x 4 to give the number of periods (quarters)
In ONE year the interest would be like this (1+.02250)4 - 1 = 1.0931 - 1 = .0931 = 9.31 % = APY