The ebook Elementary Calculus is based on material originally written by H.J. Keisler. For more information please read the copyright pages.

Geometric Approach

In geometric terms, the ε, δ condition says that for every horizontal strip (of width 2ε) centered at L, there exists a vertical strip (of width 2δ) centered at c such that whenever x ≠ c is in the vertical strip, f(x) is in the horizontal strip. The graphs in Figure 5.8.2 indicate various horizontal strips and corresponding vertical strips. They should be examined closely.


Figure 5.8.2

Last Update: 2006-11-05