Explicit Arithmetic
An=A1+(n-1)d
Example 1: 3, 7, 11, 15, 19 has a1 = 3, d = 4,
and n = 5. The explicit formula is
an = 3 + (n – 1)·4 = 4n – 1
Example 2: 3, –2, –7, –12 has a1 = 3, d = –5,
and n = 4. The explicit formula is
an = 3 + (n – 1)(–5) = 8 – 5n
http://www.mathwords.com/a/arithmetic_sequence.htm -- examples for the explicit formula.
and n = 5. The explicit formula is
an = 3 + (n – 1)·4 = 4n – 1
Example 2: 3, –2, –7, –12 has a1 = 3, d = –5,
and n = 4. The explicit formula is
an = 3 + (n – 1)(–5) = 8 – 5n
http://www.mathwords.com/a/arithmetic_sequence.htm -- examples for the explicit formula.