Find the accumulated value of an investment of $25,000 for 7 years at an interest rate of 4% if the money is a. compounded semiannually; b. compounded quarterly; c. compounded monthly d. compounded continuously

For a, b and c use this formula:
Total = Principal * (1 + rate/n)^n*years
where "n" is the number of compounding periods per year
a) semi-annual
Total = Principal * (1 + rate/n)^n*years
Total = 25,000 * (1 + .04/2) ^ 2*7
Total = 25,000 * (1.02)^14
Total = 25,000 * 1.3194787631
Total = 32,986.97

b) quarterly
Total = 25,000 * (1 + .04/4) ^ 4*7
Total = 25,000 * (1.01)^28
Total = 25,000 * 1.3212909669
Total = 33,032.27

c) monthly
Total = 25,000 * (1 + .04/12) ^ 12*7
Total = 25,000 * (1.0033333333)^84
Total = 25,000 * 1.3225138639
Total = 33,062.85

d) continuously
For continuously-compounded interest, use this formula:
Total = principal * e^(rate*years)
where "e" is the mathematical constant 2.718281828459
Total = 25,000 * e^(.04*7)
Total = 25,000 * e^(.28)
Total = 25,000 * 1.3231298123
Total = 33,078.25

Source (for formulas for a,b and c)
http://www.1728.org/compint2.htm

Source for formula for d
http://www.1728.org/compint3.htm

Compound Interest Calculator to check your work:
http://www.1728.org/compint.htm