Plot shared axis

edit

I was trying to convert this into sage. Basically print function, first derivative, second derivative all sharing the x axis. Instead of scipy.misc.derivative I'd like to use sage derivative(). I have tries for hours an got several different errors. Any ideas?

d={}
with open(source) as f:
    for line in f:
       (key, val) = line.split()
       d[str(key)] = val
       print key
       f = lambda t : eval(val)
       x = np.arange(1,20,0.01)
       first = derivative(f,x,dx=1,n=1)
       second = derivative(f,x,dx=1,n=2)
       fig,ax = plt.subplots(3,1,sharex=True)
       #plt.suptitle("\n".join(wrap(str(key + " - \n" + val), 50)))
       ax[0].plot(x,f(x))
       ax[0].set_ylabel(r'$f(x)$')
       ax[1].plot(x,first)
       ax[1].set_ylabel(r'$f\/\prime(x)$')
       ax[2].plot(x,second)
       ax[2].set_ylabel(r'$f\/\prime\prime(x)$')
       ax[2].set_xlabel(r'$x$')
       plt.savefig()
       plt.close()

The results should be something like this (i would upload my own image but I realized I cannot): http://matplotlib.org/_images/subplot...