You have two features x_1x 1 = vibration intensity, and x_2x 2 = heat generated. both x_1x 1 and x_2x 2 take on values between 0 and 1 (and are strictly greater than 0), and for most "normal" engines you expect that x_1 \approx x_2x 1 ≈x 2 . one of the suspected anomalies is that a flawed engine may vibrate very intensely even without generating much heat (large x_1x 1 , small x_2x 2 ), even though the particular values of x_1x 1 and x_2x 2 may not fall outside their typical ranges of values. what additional feature x_3x 3 should you create to capture these types of anomalies: