Answer:
a. 1/2
b. 512
c. 1024
Explanation:
The nth term of a geometric progression can be written as;
Tn = ar^n-1
where a is the first term, r is the common ratio and n is the term number
From the question;
Fifth term = ar^4 = 32
Eight term = ar^7 = 4
a. We want to find the common ratio
What to do here is that we can divide the 8th by the 5th term
ar^7/ar^4 = 4/32
r^3 = 1/8
r^3 = (1/2)^3
Thus r = 1/2
b. First term
we can make a substitution in any of the two given terms
Let’s use the fifth term
ar^4 = 32
a * (1/2)^4 = 32
a * 1/16 = 32
a = 16 * 32
a = 512
C. Sum of the first 50 terms
To calculate this, we use the sum of terms formula
Sn = a(1- r^n)/1-r
a = 512 , n = 50 and r = 1/2
Making the substitution;
Sn = 512(1-(1/2)^50)/1-1/2
Kindly note that (1/2)^50 will be infinitesimally small and will be close to zero
So we can approximate (1/2)^50 to be zero
Hence;
Sn = 512(1-0)/0.5
Sn = 512/0.5
Sn = 1024