Out in Space

Students: Don't be deterred if you have not learnt the method of solving differential equations by separation of variables because all you have to do is to rearrange the equation in the form $$\int f(v) dv = \int f(x) dx$$ so that you can integrate both sides and the rest is easy integration.

Teachers: This is an example you might use to launch into work on learning the method of separation of variables.