BYU Math 110 Final Exam questions and answers

BYU Math 110 Final Exam
questions and answers.
What equation(s) would I use to solve:


Find a10 if a2 = 5 and r = 3 - answer An = ar^(n-1)


and I would solve it like this:


A2 = ar^(2-1) = ar^1
A10 = ar^(10-1) = ar^9
Which leaves us with a^8


Then after solving for R's exponent, I would plug in the values of a2
and r to find a10:


a10 = (a2)(r^8)
a10 = (5)(3^8) = 32805


What equation(s) would I use to find the answer to this problem:


A5 = (8/375) A8 = (64/46,875) Determine A and R - answer an =
ar^(n-1)




First I'd solve for r by diving the equation for a8 by the equation for
a5.

, (64/46875) = ar^(8-1) = ar^7
divided by
(8/375) = ar^5-1 = ar^4


Therefore:
8/125 = r^3
and
r = 2/5


Once I have R, I'd solve for A by plugging R into one of the
equations.
So,
a5 = (8/375) = a(2/5)^5-1
turns out to be:
a = 5/6


r = 2/5 and a = 5/6


What equation(s) would I use when evaluating this sum:


Lower limit: k=1
Upper limit: infinity


5(1/5)^(k-1) - answer a1 / (1-r)


How do I know if a sum converges? And what does 'converge' mean?
- answer If r is between 1 and -1