Question

Find the tenth term of the geometric sequence, given the first term and common ratio.

a1=4 and r=1/2

Answer 1

1/128

Explanation:

Answer 2

`a_(10)=(1)/(128)`

Explanation:

In the geometric series:

`a_1=4\\ \\r=(1)/(2)`

The nth term of the geometric sequence can be calculated using formula

`a_n=a_1\cdot r^(n-1)`

In your case, n = 10, then

`a_(10)\\ \\=4\cdot \left((1)/(2)\right)^(10-1)\\ \\=4\cdot \left((1)/(2)\right)^9\\ \\=2^2\cdot (1)/(2^9)\\ \\=(1)/(2^(9-2))\\ \\=(1)/(2^7)\\ \\=(1)/(128)`