Arithmetic Sequence - Example

Find the 50th term of the sequence $7, 11, 15, 19, ...$

First, identify $a_1 = 7$ and $d = 4$ (each term increases by $4$). Then use the formula: $a_{50} = 7 + (50 - 1) \times 4 = 7 + 196 = 203$.

Without the formula, you would need to compute 49 additions. With the formula, you get the answer in one step. This is the power of closed-form expressions.