So some quick tips for inequalities:
**What you do to one side you HAVE TO do it to the other 2**
**If you ever divide a negative number past the inequality signs, the signs FLIP!!**
(e.g. 2>-5x>25)
-2/5 <x < -5
I hope that this has helped!
The question is an annuity question with the present value of the annuity given.
The
present value of an annuity is given by PV = P(1 - (1 + r/t)^-nt) /
(r/t) where PV = $61,600; r = interest rate = 9.84% = 0.0984; t = number
of payments in a year = 6; n = number of years = 11 years and P is the
periodic payment.
61600 = P(1 - (1 + 0.0984/6)^-(11 x 6)) / (0.0984 / 6)
61600 = P(1 - (1 + 0.0164)^-66) / 0.0164
61600 x 0.0164 = P(1 - (1.0164)^-66)
1010.24 = P(1 - 0.341769) = 0.658231P
P = 1010.24 / 0.658231 = 1534.78
Thus, Niki pays $1,534.78 every two months for eleven years.
The total payment made by Niki = 11 x 6 x 1,534.78 = $101,295.48
Therefore, interest paid by Niki = $101,295.48 - $61,600 = $39,695.48
This sequence has generating function

(if we include
for a moment)
Recall that for
, we have

Take the derivative to get


Take the derivative again:


Take the derivative one more time:


so we have

Change the mixed numbers into improper fractions:
5/3 X 9/2
Reduce - the 3 and 9 can be simplified
5/1 X 3/2
multiple numerators and denominators
15/2
Not sure how you need the answer - i would change it into a mixed number
7 1/2