In the first order differential equation
dy/dx=f (x, y) the function f (x, y) is a function of the ratio y/x:
dy/dx=g (y/x)
Show that the substitution of U=y/x leads to separable equation in U and x.
The decay of a population by catastrophic two body collisions is described by
dN / dt =- kN2.
where 2 is supersubscribe
derive the solution.
N(t)=No (1+ t/T) -1,where o is subscribe and -1
Supersubscribe
The general solution of
d2B/dr2+dB/rdr-B/a^2 =0
is B=C Io(r a) +D Ko(r/a)
In our particular case the solution is Ko.
How we get
B= (h/2 phi a^2) Ko(r/a)
Where h= magnetic flux= Integral B d2r. Phi=3.14. And a=(m/meu. n e^2) 1/2