import numpy as np
import matplotlib.pyplot as plt


def main():
    f_s = 48
    T_s = 1/f_s
    t = np.arange(-1, 1, T_s)

    f = 3
    omega = 2*np.pi*f
    signal = np.cos(omega*t)

    plt.stem(t, signal)
    plt.show()

if __name__ == "__main__":
    main()