### Author Topic: Text Book 2.4 Example 2.1  (Read 263 times)

#### Yifei Hu

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##### Text Book 2.4 Example 2.1
« on: February 19, 2022, 09:16:55 PM »
In this problem, $-1 < t < -\infty$, when applying D' Alembert's formula, why we integrate from 0 to t instead of from -1 to t?
We integrate from $t=0$ because for $t=0$ initial conditions are done. $-1<t$ is a domain where $f(x,t)$ is defined