Express the sum of 28 terms of the series of this sequence using sigma notation.

Explanation

To express the sum of the first 28 terms of the sequence 2, 5, 8, ..., we need to determine the general term of the sequence and then represent the sum using sigma notation.

### Step-by-Step Solution:

1. **Identify the Sequence**:
The given sequence is 2, 5, 8, ... This is an arithmetic progression (AP) where:
- First term \( a = 2 \)
- Common difference \( d = 5 - 2 = 3 \)
...