Stepik 2.2.6Kapica

import matplotlib.pyplot as plt
import math


def compute_population(T1, t, tau, C):
    under_atan = (T1 - t) / tau
    arcctg = math.pi / 2 - math.atan(under_atan)
    N_t = (C / tau) * arcctg
    return N_t

C = 172  # billion man years
T1 = 2000  # year 2K;
tau = 45  # 45 years old;

range_start_a = 2000  # start of the range
end_range_b = 2020  # End of the range
n =20 #количество точек построения
step_h = (end_range_b-range_start_a)/(n-1)  # calculate the step(dunno what the step)

# Let's form lists with argument values and function values in them

x_list = [range_start_a + step_h * i for i in range(n)]
f_list = [compute_population(T1, t, tau, C) for t in x_list]

#5. Построим линию графика, установим для нее цвет и толщину:

line = plt.plot(x_list, f_list)

plt.setp(line, color="blue", linewidth=2)
#6. Выведем 2 оси, установим для них позицию zero:

plt.gca().spines["left"].set_position("zero")

plt.gca().spines["bottom"].set_position("zero")

plt.gca().spines["top"].set_visible(False)

plt.gca().spines["right"].set_visible(False)

plt.show()