To find the sum of a geometric series, we can use the formula:
Sn = a(1 - r^n) / (1 - r),
where Sn is the sum of the series, a is the first term, r is the common ratio, and n is the number of terms.
In the given series, the first term (a) is 16, and the common ratio (r) is 1/2. We need to find the number of terms
.
To find n, we can use the formula for the nth term of a geometric sequence:
an = a * r^(n-1).
In this case, we need to find when the nth term is equal to 1. So we have:
1 = 16 * (1/2)^(n-1).
Dividing both sides of the equation by 16, we get:
1/16 = (1/2)^(n-1).
To simplify the equation, we can write both sides with the same base:
2^(-4) = 2^(1-n).
Since the bases are equal, the exponents must be equal:
-4 = 1 - n.
Solving for n, we have:
n = 1 + 4 = 5.
Therefore, the number of terms in the series is 5.
Now, we can plug the values of a = 16, r = 1/2, and n = 5 into the formula for the sum of the series:
Sn = 16(1 - (1/2)^5) / (1 - 1/2).
Simplifying:
Sn = 16(1 - 1/32) / (1/2).
Sn = 16(31/32) / (1/2).
Sn = 16 * (31/32) * (2/1).
Sn = 31.
Hence, the sum of the series 16, 8, 4, 2, 1 is 31.