Find the accumulated amount A if the principal P is invested

Find the accumulated amount A, if the principal P is invested at an interest rate of r per year for t years.
P = $1300, r = 4%, t = 10, compounded semiannually

Actually as it is compounded semianually, it is equivalent to P = $1300, r = 2%, t = 20, so A = P ( 1-r)^t = 1300*(1.02)^20 = $ 1931.73