A false rule for the cosine of a double angle is tested on five angles. What does this print? import numpy as np; a = np.radians(np.arange(0, 181, 45)); left = np.cos(2 * a); right = 2 * np.cos(a) - 1; print(np.allclose(left, right), int(np.sum(np.isclose(left, right))))