Name ________________________   Logic Homework 9.  Date ______________

Circle the valid arguments, and cross out the invalid ones.

1. ~Py
    Qz ^ Py
    Qz	
2. Rm ^ Sn
    Sn
    Rm	
3. Bk v Cl
    Cl ^ Bk
	
4. Fo
    Gp ^ Fo
	
5. ~To
    To ^ Up
    Up	
6. Lu v Mv
    ~Mv
    Lu	

7. Hq v Ir
    ~Hq
    ~Ir	
8. Js v Kt
    Js
    ~Kt
	
9. Xs ^ ~Yt
    Yt v Zu
    Zu
	
10. Av v Bw
     ~Bw
     Bw v Cx
     Cx ^ Av	
11. Nw
      Ox v Nw
      Ox
	
12. ~Io
     (He v Ni) v Io
      He ^ Ni

13. Ho v Ju
      Ju v Ho	
14. Le ^ Ii
      Ii ^ Le	
15. Tc v Ud
      Tc ^ Ud	
16. Xg
      Xg ^ Yh	
17.Ra ^ Sb
     Ra v Sb	
18. Dm
      En v Dm	

Prove the following arguments valid by DERIVATION. 

19.  Ia v Mu			1. Show  							
       No v (Mu v Ia)		
				2. 								
				
				3. 								
				
				4. 								
				
				5. 								

20. (Ie ^ Hi) v Gu		1. Show  							
      ~Gu				
      Hi ^ Ie			2. 								

				3. 								
				
				4. 								
				
				5. 								

21. Iu v (Ge ^ He)		1. Show  							
      ~Iu						
      He v Ge			2. 								

				3. 								
				
				4. 								
				
				5.