Question

Write an
explicit formula for an, the nth term of the sequence 63, 21, 7,

Answer 1

`\Large \boxed{\sf 7 * 3 ^(3-n)}`

Step-by-step explanation:

This is a geometric sequence

Use nth term of geometric sequence formula

`a_1 * r^(n-1)`

Ratio is 27/63=1/3

First term is 63

`\displaystyle 63 * ((1)/(3)) ^(n-1)`

Simplify expression

`\displaystyle 7 * 3 ^(3-n)`