Численные методы

from numpy import arange
from math import fabs


def lagranz(x, y, t):
    z = 0
    for j in range(len(y)):
        p = 1
        for i in range(len(x)):
            if i != j:
                p *= (t-x[i])/(x[j]-x[i])
        z += p * y[j]
    return z


def tabulate_point(x, e):
    a = x
    y = a
    n = 0

    while fabs(a) > e:
        q = - pow(x, 2) * (2*n+1) / (pow(2*n+3, 2)*(2*n+2))
        a = q * a
        y += a
        n += 1

    return y


def tabulation(a, b, count, e):
    x_points = []
    f_arr = []
    h = (b - a) / count
    for x in arange(a, b, h):
        f = tabulate_point(x, e)
        x_points.append(x)
        f_arr.append(f)
    return x_points, f_arr


x_arr, y_arr = tabulation(0, 4, 10, pow(10, -6))
x_arr1, y_arr1 = tabulation(0, 4, 5, pow(10, -6))
for i, j in zip(x_arr, y_arr):
    z = lagranz(x_arr1, y_arr1, i)
    print('%.1f : %f : %f' % (i, z, z - j))