
An arithmetic sequence is an ordered list of numbers when the difference of any two successive numbers is constant. An arithmetic series is the sum of an arithmetic sequence. This Program can also calculate the nth term of geometric sequences, find the number of terms in an geometric sequence and find the sum of geometric sequences.

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| Arithmetic Sum | Arithmetic Term | Geometric Sum | Geometric Term |
| Outline: | |||
| Line 1. | Clear Screen | ||
| Line 3 - 7. | Prep (strings) | ||
| Line 8. | Menu | Menu (Arith/Geo) | |
| Line 10. | Lbl A Arithmetic Sequence | ||
| Line 11 - 13. | Input (Arithmetic Sequence) | ||
| Line 14 - 16. | Formula (Arithmetic Sum) | ||
| Line 18. | Arithmetic Sum | ||
| Line 22. | Arithmetic (nth) Term | ||
| Line 23 - 25. | Input (Arithmetic (nth) Term) | ||
| Line 26. | Formula (Arithmetic Term) | ||
| Line 28. | nth Term | ||
| Line 32. | Lbl G Geometric Sequence | ||
| Line 33. | Menu | Menu (Finite/Infinite) | |
| Line 34. | Finite Sequence | ||
| Line 35 - 37. | Input (Finite Sequence) | ||
| Line 38. | Formula (Finite Sum) | ||
| Line 40. | Geometric Sum | ||
| Line 43. | Infinite Sequence | ||
| Line 45 - 46. | Input (Infinite Sequence) | ||
| Line 49. | Formula (Infinite Sum) | ||
| Line 51. | Infinite Series Sum | ||
| Examples | |||
| Series Formulas | |||
| Reference Commands | |||
| Reference Links |
| Arithmetic Sequence | Geometric Sequence | |
| F = First Term | F = First Term | |
| L = Last Term | L = Last Term | |
| D = Common Difference | R = Common Ratio | |
| S = Arithmetic Sum | S = Geometric Sum | |
| S = ((L - (F - D)/ D)(F + L ))/2 | S = (F - (L*R))/(1- R) | |
| Find the sum of the sequence: | Find the sum of the sequence: | |
| 1 + 2 + 3 ...985 | 5 + 10 + 20 ...640 | |
| Answer: 485605 | Answer: 1275 | |
| S = ((985 - (1 - 1)/ 1)(1 + 985))/2 = 485605 | S = (5 - (640 * 2))/(1 - 2) = 1275 | |
| To find the sum of a certain number of terms of an arithmetic sequence: ![]() where Sn is the sum of n terms (nth partial sum), a1; is the first term, an; is the nth term. | To find any term of an arithmetic sequence: where a1 is the first term of the sequence, d is the common difference, n is the number of the term to find. |