Math Formulas Memorization

Explicit Formula: Use this to find any specific term (\(n\)) without knowing the ones before it. An=a1+(n-1)d

Finite Sum (Partial Sum): Use this to find the total of the first \(n\) terms. Sn=(n/2)(A1+An)

Explicit Formula: Use this to find the \(n^{th}\) term. An=A1 x R^(n-1)

Recursive formula: An=An-1 x R

Finite Sum (Partial Sum): Use this for a set number of terms. Sn=(a1) (1-r^n) / (1-r)

Infinite Sum: Use this only if the sequence "shrinks" toward zero (where \(|r| < 1\)). If \(|r| \geq 1\), the sum does not exist (it diverges). Sinfinate = (A1) / (1-R)