Formulas

Question 1

What is the formula for the nth term of an arithmetic sequence?

Answer 1

u = a + (n-1)d a is the first term d is the common difference

Question 2

How do you find the sum of n terms in an arithmetic sequence when you have the first term and the common difference?

Answer 2

S = n/2 (2a + (n-1)d)

Question 3

How do you find the sum of n terms in an arithmetic sequence when you have the first term and the last term?

Answer 3

n/2 (a + l) where l is the last term

Question 4

A geometric sequence has a _____ ______ between consecutive terms. To get from one term to the next you ______ by the ______ _____.

Answer 4

A geometric sequence has a common ratio between consecutive terms. To get from one term to the next you multiply by the common ratio.

Question 5

What is the formula for the nth term in a geometric sequence?

Answer 5

ar^n-1 where a is the first term and r is the common ratio

Question 6

The sum of the first n terms in a geometric series is given by what formula?

Answer 6

Question 7

find x:

a^x = n

Answer 7

log_an = x