For Each given geometric sequence, find the sum of the first:

1. 8 terms of 0.2,0.02,0.002,...?
2. 6 terms of 1/2,1/4,1/8,...?
3. 5 terms of 5/2,15/2,45/5,...?
4. 7 terms of 0.25,1,4,16,...?​