Вариант 4 / 2 / 2Newton

matrix = [(0.2, -4.024), (0.25, -3.95), (0.3, -3.8610), (0.35, -3.7555)]
'''for i in range(4):
print(matrix[i])'''
a = 0.21
delta = [(matrix[1][1] - matrix[0][1]), (matrix[2][1] - matrix[1][1]), (matrix[3][1] - matrix[2][1])]
sqdelta =(delta[1] - delta[0], delta[2] - delta[1])
tripdelta = sqdelta[1] - sqdelta[0]
'''print(delta)
print(sqdelta)
print(tripdelta)'''
q = (a - matrix[0][0]) / 0.05
'''print(q)'''
print('1', matrix[0][1] + delta[0] * q, (matrix[0][1] + delta[0] * q + sqdelta[0]*q*(q-1)/2) - (matrix[0][1] + delta[0] * q)) # Первая итерация
print('2', matrix[0][1] + delta[0] * q + sqdelta[0]*q*(q-1)/2, (matrix[0][1] + delta[0] * q + sqdelta[0]*q*(q-1)/2 + tripdelta*q*(q-1)*(q-2)/6) - (matrix[0][1] + delta[0] * q + sqdelta[0]*q*(q-1)/2)) # Вторая итерация
print('3', matrix[0][1] + delta[0] * q + sqdelta[0]*q*(q-1)/2 + tripdelta*q*(q-1)*(q-2)/6, '-') # Третья итерация