Arithmetic Sequences
Key points
- An arithmetic sequence is a sequence in which you add or subtract a constant after each term.
- Use the formula for arithmetic sequences to find any number in the sequence or to solve for unknown values.
Arithmetic Sequences are sequential lists of terms in which you add or subtract a constant to find the next term. An example of an arithmetic sequence is seen to the right.
- In this example, the first term is 5, and 3 is being added each time.
- The constant, or the difference, is expressed as a positive number when adding and a negative number when subtracted.
Formula Booklet
The key variables of an arithmetic sequence are the first term (u1) , the difference (d) , and the number of terms (n). They are shown in the formula to the left.
- This formula is used to find any number in the sequence (un), commonly known as the nth term.
- Solve for any other variable algebraically.
Apart from this formula, arithmetic sequences can be generally expressed with the model shown to the right.
- This models the common difference being added multiple times.
Not in Formula Booklet but important
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