1. 1 A Mathematical Model of Flu with Asymptomatic Infection Sze-Bi Hsu Department of Mathematics National Tsing-Hua University, Hsinchu, Taiwan Ying-Hen Hsieh Department of Applied Mathematics National Chung-Hsing University, Taichung, Taiwan

2. 2 Model Variables

3. 3 Assumptions

4. 4

5. 5 The model without quarantine

6. 6 Parameters

7. 7 Mathematical Analysis

8. 8

9. 9 Analysis of limiting System

10. 10

11. 11 Stability Analysis of System (3)

12. 12

13. 13

14. 14

15. 15

16. 16

17. 17

18. 18 Predictions

19. 19 case 1.1

20. 20

21. 21 case 1.2(a)

22. 22

23. 23 Case 1.2(b)

24. 24

25. 25 Case 1.3

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27. 27

28. 28

29. 29

30. 30

31. 31 Case 4.1

32. 32

33. 33 Case 4.2

34. 34

35. 35 Discussion