## Calculus (3rd Edition)

The right endpoints are $$2.5, \quad 3, \quad 3.5, \quad 4, \quad 4.5, \quad 5$$ and the left endpoints are $$2, \quad 2.5, \quad 3, \quad 3.5, \quad 4, \quad 4.5$$
We have $\Delta x=\frac{5-2}{6}=0.5$; now the right endpoints are $$2.5, \quad 3, \quad 3.5, \quad 4, \quad 4.5, \quad 5$$ and the left endpoints are $$2, \quad 2.5, \quad 3, \quad 3.5, \quad 4, \quad 4.5$$ See page 226 in the book for examples.