# Hatcher 0.29

Hatcher, Algebraic Topology, Chapter 0

29. In case the CW complex $X$ is obtained from a subcomplex $A$ by attaching a single cell $e^n$, describe exactly what the extension of a homotopy $f_t:A\to Y$ to $X$ given by the proof of Proposition 0.16 looks like. That is, for a point $x\in e^n$, describe the path $f_t(x)$ for the extended $f_t$.

Proof.

$\square$