Sequences and Series Test

State whether the followng sequence is arithmetic, geometric or neither:

6.6, 7.7, 8.8, 9.9….

State whether the followng sequence is arithmetic, geometric or neither:

\frac{1}{2}, -2, 6, -18…..

State whether the followng sequence is arithmetic, geometric or neither:

a_n = {3^n} + 1

What will be the 55^{th} term of the arithmetic sequence: -15, -9, -3, 3, 9…..?

Find the 16^{th} term of the sequence: -81, 27, -9, 3…..

Give your answer as a fraction and show you have used the correct formula for the nth term

Which term will 168 be in the sequence: -7, -2, 3, 8…..?

Find and simplify a formula for the nth term of:

27, 18, 12, 8….

Find and simplifya formula for the nth term of:

5, 9, 13, 17….

In a geometric sequence, a_1= 6 and a_4= 750. Find the 8^th term.

Evaluate:

\sum_{n=1}^{5} 3(-4)^{n-1}

Find S_{15} of 11 + 7 + 3 + -1 + -5…..

Find S_{10} of 16 + 8 + 4 + 2…

Keep your answer as a fraction.

Find the sum of infinity of the series 320, 80, 20, 5….

Write your answer as a fraction

In an arithmetic series S_{10}= 1515 and a_1 = 3. Find the common difference, d.

A recursive sequence is defined by a_1= -1 and a_{n+1}= 3a_n+ 5. Find a_5.

An employee makes bank deposits as follows: $12.20 the first month, $13.70 the next month, $15.20 the third month and so on for twelve years. Find the sum of the deposits

A city has a population of 20,000 in 2000 and the population is increasing by 1.5% every year. What will the population be after 15 years?