# Differential equation

1. May 3, 2009

### kasse

$$\frac{dN}{dt}=-k_sN^2$$

Attempt:

$$\frac{1}{N^2}dN = -k_s dt$$

Integrate:

$$-\frac{1}{N} + C = -k_s t$$

In the solution manual, C is written [/tex]\frac{1}{N_0}[/tex]

Why?

2. May 3, 2009

### dx

You posted this already and I replied to it in the other thread.