For the geometric series shown, a1 = ½ and r = ½. One-half + one-fourth + one-eighth + one-sixteenth + StartFraction 1 Over 32 EndFraction + StartFraction 1 Over 64 EndFraction Study the work shown to find the partial sum for these 6 terms. S Subscript 6 Baseline = StartFraction one-half left-bracket 1 minus (one-half) Superscript 6 Baseline right-bracket Over 1 minus one-half EndFraction = StartFraction one-half left-bracket 1 minus StartFraction 1 Over 64 EndFraction right-bracket Over one-half EndFraction = StartFraction one-half left-bracket 1 minus StartFraction 63 Over 64 EndFraction Right-bracket Over one-half EndFraction = StartFraction 63 Over 64 EndFraction Identify a1 and r for the geometric sequence defined by a Subscript n Baseline = negative 256 (negative one-fourth) Superscript n minus 1 a1 = r =