Answer:
B. 6/5, 12/25, 24/125
Step-by-step explanation:
Let the geometric means to be inserted be x, y and z. The geometric series will contain 5 terms as shown:
3, x, y, z, 48/625
Using the nth term of a geometric sequence to find the missing term.
[tex]Tn = ar^{n-1}[/tex] where:
a is the first term
n is the number of terms and
r is the common ratio
From the sequence, a = 3
[tex]T5 = 3r^{5-1} \\T5 = 3r^{4}[/tex]
Since the fifth term is 48/625 then:
[tex]3r^{4}=\frac{48}{625} \\r^{4}= \frac{48}{625*3} \\r^{4} = \frac{16}{625} \\r=\sqrt[4]{\frac{16}{625} } \\r = \frac{2}{5}[/tex]
To get the 2nd, 3rd and 4th term, we will substitute the value of the first term and the common ratio in the equation given.
[tex]T2 = 3(\frac{2}{5} )^{2-1}\\ T2 = 3*2/5\\T2 = 6/5[/tex]
when n = 3;
[tex]T3 = 3(\frac{2}{5} )^{3-1}\\ T3 = 3*(\frac{2}{5} )^{2} \\T3= 3*4/25\\T3 = 12/25[/tex]
when n = 4;
[tex]T4 = 3(\frac{2}{5} )^{4-1}\\ T4 = 3*(\frac{2}{5} )^{3} \\T4= 3*8/125\\T4 = 24/125[/tex]
The three positive geometric mean are 6/5, 12/25, 24/125
