Question

1.2,3,7.5,18.75 which formula can used to describe the sequence?

Answer 1

Answer:

$a_n=1.2 \cdot 2.5^{n-1}$

Step-by-step explanation:

The first step is to realize that this is a geometric sequence, where each next term in the sequence is 2.5 times larger than the previous. You can confirm this by the fact that 3=1.2*2.5, 7.5=3*2.5, and 18.75=7.5*2.5. Now, you can write the formula, where n is where the number is in the sequence, and a is the number itself. Since 1.2 is the first term in the sequence and the rate of expansion is 2.5, the formula is:

$a_n=1.2 \cdot 2.5^{n-1}$

Hope this helps!