def graph(): #График
    from matplotlib import pyplot as plt
    global start, end, step, eps
    xlist = np.linspace(start.get(), end.get(), 10000, dtype = float)
    ylist = []
    xlist1 = []
    for x in xlist:
        if fabs(f2(x)) <= 1e-3:
            ylist.append(f1(x))
            xlist1.append(x)
    plt.plot(xlist, [f1(x) for x in xlist])
    plt.plot(xlist1,ylist, "rs")
    plt.plot(xlist, np.zeros(10000, dtype = float), color = 'red')
    plt.grid(b = True)
    plt.show()