What is the explicit formula for this geometric sequence? 5,10,20,40,80,

  an = 5·2^(n-1)

Step-by-step explanation:

The explicit formula for a geometric sequence with first term a1 and common ratio r is ...

  an = a1·r^(n-1)

Your sequence has a1=5 and r=2, so the explicit formula is ...

  an = 5·2^(n-1)

cheater

step-by-step explanation:

whole numbers.

step-by-step explanation:

we are given the average monthly rainfall (in millimeters) model r(m) for the years 1900-2009 as a function of the month number m.

as we can see m is taken for the number of months for years 1900-2009.

we know that number of months can't be a negative number or decimal number or a fraction.

so, the number of months could be only positive whole numbers.

therefore, whole numbers is more appropriate for the domain of r.