Question about the constant C

[Yuemile Wang]

 C is arbitrary but  how to find a way to determine C with an exact number. Can I just let the initial condition to be 0, then get C=0  with the corresponding equilibrium.  Also I found in Chapter 2.1, C is equal to 1 for many differential equation.

[Victor Ivrii]

As long as we have just an equation constant $C$ (and from Chapter 3 constants $C_1$, $C_2$, … , $C_m$ where $m$ is an order of equation) is arbitrary. We need initial conditions to find them. There is no significance in $C=0$ or $C=1$ etc