when expressing a geometric series, sn is used. identify an equivalent means of expressing a geometric series for n terms.(1 point) responses ∪nn=1 union underscript n equals 1 overscript n end scripts πnn=1 upper pi underscript n equals 1 overscript n end scripts ∩nn=1 intersect underscript n equals 1 overscript n end scripts ∑nn=1