import matplotlib, sys, os, gc
matplotlib.use("wxAgg")
matplotlib.interactive(True)

from pylab import *

sys.path.append(r"c:\py\lib")

os.chdir(r"c:\py")

def dellastplot(): del gca().lines[-1]

def Tns(Tsp): return (Tsp**2 - 0.07)**0.5
    
def Tsp(Tns): return (Tns**2 + 0.07)**0.5

def printx(): print('%.1f +- %.1f Hz' % (mean(xlim())*1e3 - 50e3, std(xlim())*1e3))