First thing you want to do is write down the equation your going to use for Feature Value,
A = P ( 1 + r/n )^{nt }were P= principle , r= intrest Rate , n= # times per year, t= total time, and A your Feature Amount.
There fore A = 3,400 ( 1 + .12/2)^{2(5)} by substituting all the given values.
Notice that The Rate of 12% became .12 by dividing 12/100, This is due to the fact that the percentage value can not be use to simplify the problem , Therefore it needs to be converted to a decimal value.
Also your "n" value is 2, since its compounded semiannually, every 6 months, which means 2 times a year.
The Algebra part can be confusing at times... Take it step by step
1. ( 1 + .12/2) = ( 1 + .06) = 1.06
2. (1.06)^{2(5) }= (1.06)^{10} = 1.7908477
3. 3,400 * ( 1.7908477) = 6088.88218
4. A = $ 6088.88
10/30/2012

Emmanuel G.