How to use Trapezoidal sum to approximate the area from a table

The video tutorial explains how to factor out constants like 1/2 and Delta X in mathematical expressions, particularly when using the trapezoid rule for integration. It highlights the importance of uniformity in Delta X and demonstrates how to simplify expressions by recognizing patterns and symmetry. The tutorial concludes with a final calculation, ensuring the result is correct.

What does the speaker mean by 'all these middle terms, they get added twice'?

Describe the final simplification process mentioned in the text.