How to write an expression for the nth term?

Question

I have this equation here and i am completely stuck. Any tip on soliving this problem?

1+(1/2).... 1+(3/4) 1+ (7/8) 1+ (15/16)

Answer 1

Your 1st term, a[1], is 2 - (1/2)^1,
a[2] = 2 - (1/2)²
a[3] = 2 - (1/2)³
so nth term will be
a[n] = 2 - (1/2)^n

Answer 2

1 + (2^(n) -1)/ 2^n

Answer 3

term 1 : 1+(1/2)=1+((2^1 -1)/2^1)
term 2 : 1+(3/4)=1+((2^2 -1)/2^2)
term 3 : 1+(7/8)=1+((2^3 -1)/2^3)


term n : =1+((2^n -1)/2^n)