I need help with a word problem. I thought I new how to do this, but apparently not.

"Following the birth of his child, Juan deposits $10,000 in a trust fund where interest is 6.4% compounded semiannually. "

A) Find a function for the amount in the account after t years.

This should be A=10,000(1+.64/2)^2(t) ???????

B)Find the amount of money in the account at t= 0,4,8,10,18. I just need to know how to do this part. I put this in on my calculator but the numbers don't seem realistic.

A = 10,000(1+.64/2)^(2*0) , this one equals $10,000

A = 10,000(1+.64/2)^(2*4) , I'm getting 92170.39521

What am I doing wrong?