y derivative of the fourth (4th) order minus 4y derivative of the third (3rd) order plus 8y two strokes of the second (2nd) order minus 8y stroke first (1st) order plus 4y equally 0
y derivative of the fourth (4th) order minus 4y derivative of the third (3rd) order plus 8y two strokes of the second (2nd) order minus 8y stroke first (1st) order plus 4y equally zero