Middle term property (arithmetic)

a_n=\dfrac{a_{n-1}+a_{n+1}}{2}

Result unit: — (liczba)

What it describes

Every term of an arithmetic sequence (except the endpoints) is the arithmetic mean of its neighbors.

a_n

middle term

a_{n-1}, a_{n+1}

neighboring terms

In an arithmetic sequence every term lies exactly midway between its neighbors — this is a test for being arithmetic.

Checking whether a sequence is arithmetic; problems with three consecutive terms.

The neighboring terms are 4 and 10. Compute the middle term.

Substitutionneighbors: 4 and 10.

Result

a=\dfrac{4+10}{2}=7

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