Express the series `2+4+6+…+20` in sigma notation.

Explanation

To express the series \(2 + 4 + 6 + \ldots + 20\) in sigma notation, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Pattern**:
The series consists of even numbers starting from 2 and ending at 20. The terms are \(2, 4, 6, 8, 10, 12, 14, 16, 18, 20\).

2. **Determine the General Term**:
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