Question

I have to find the five terms in geometric sequence in this

a(lower n)= (2)^n-1

I would do it 2(1)+2(2)+(2(3)+2(4)+2(5)

so 2,4,6,8,10

Did I do this correctly??

Answer 1

Nope. 2^n goes
2,4,8,16,32,64,...

So, 2^n-1 goes
1,3,7,15,31,63,...

Your sequence is 2*n, not 2^n

Answer 2

Actually, none of the sequences I gave is a geometric sequence. For that you need

an = 2^(n-1)
1,2,4,8,16,...

where each pair of terms has a common ratio, in this case, 2.