I have this code to solve a simple first order ODE using odeint. I managed to plot the solution y(r), but I also want to plot the derivative y'= dy/dr. I know y' it is given by f(y,r), but I'm not sure how to call the function with the output of the integration. Thank you in advance.

```
from math import sqrt
from numpy import zeros,linspace,array
from scipy.integrate import odeint
import matplotlib.pylab as plt
def f(y,r):
f = zeros(1)
f[0] = -(y[0]*(y[0]-1.0)/r)-y[0]*(2/r+\
((r/m)/(1-r**2/m))*(2*sqrt(1-r**2/m)-k)/(k-sqrt(1-r**2/m)))\
-(1/(1-r**2/m))*(-l*(l+1)/r+\
(3*r/m)*(k+2*sqrt(1-r**2/m))/(k-sqrt(1-r**2/m)))\
+((4*r**3)/((m**2)*(1-r**2/m)))*(1/(k-sqrt(1-r**2/m))**2)
return f
m = 1.15
k = 3*sqrt(1-1/m)
l = 2.0
r = 1.0e-10
rf = 1.0
rspan = linspace(r,rf,1000)
y0 = array([l])
sol = odeint(f,y0,rspan)
plt.plot(rspan,sol,'k:',lw=1.5)
```