Yes its 1, because r is always equal to 1
Yes :) and kapag r is equal to 1, may shortcut sa paghanap ng geometric sum

Ganito po kasi yung question. In a geometric sequence , can be r equal to 1? Can be r equal to -1? What happens in each of these cases?
example, sa geometric sequence na 2,2,2,2,2, r = 1, kapag ganun, the geometric sum will be the product of the first term and the number of terms
I guest r is not can equal in -1
Tapos kapag r = -1 naman, say for example 3, -3, 3, -3, 3, kapag n is an odd number, the geometris sum is the first term itself. kapag naman n is an even number, the geometric sum is 0. :)