Find s5 for a geometric series for which a1=81 and r=1/9.

ANSWER

EXPLANATION

The sum of the first terms of a geometric sequence is given by;

Where , is the number of terms and is the first term.

When , we have , we get;

answer: 1+1

step-by-step explanation: 1+1 is at least 2

the revenue of the fitness center, y, is the product of two factors: the number of members and the fee paid by each member. there are 320 members now, but number of members goes down by 10 for each $5 increase in fees, so if x is the number of $5 price increases then members is equal to (320 - 10x). since the fee is currently $45, and the fee increases by $5 for every price bump x, the fee is given by (45 + 5x). so, revenue y is given by y = (320 - 10x)(45 + 5x).