7. Arithmetic Sequences
Sign In
Substitute 2, 4, and 11 for n.
Second: 2
Fourth: 12
Eleventh: 47
To find certain terms in a sequence described by an explicit formula, substitute the number of the desired term into the given formula to get the term's value.
A(n)=-3+(n-1)(5)
n= 2
Subtract term
Identity Property of Multiplication
Remove parentheses
Add terms
Now, let's do the same thing for the fourth and eleventh terms.
| n^(th) term | -3+(n-1)(5) | A(n) |
|---|---|---|
| 2 | -3+( 2-1)(5) | 2 |
| 4 | -3+( 4-1)(5) | 12 |
| 11 | -3+( 11-1)(5) | 47 |
The second, fourth, and eleventh terms are 2, 12, and 47.