import numpy as np
import matplotlib.pyplot as plt

def f(x):
    return x**2 + 1

dx = 0.1

x_array = np.arange(-2, 2+dx, dx)
n = len(x_array)
y_array = np.zeros(n)

for i in range(0, n, 1):
    y_array[i] = f(x_array[i])

plt.close('all')
plt.plot(x_array, y_array, label='y')
plt.legend()
plt.xlabel('x')
plt.grid()

# plt.savefig('plot_fun_2ord.pdf')
plt.show()