64. a) k x k

    
2
2 2
3
b) k x k
 
      
5
4 12
c) k x arctg k

      
3
2 2
4 4
d) k x k ; k x k ;
k x k
  
          

      
5 3
2 2 2 2
4 2 4
2 2
2
e) k x k ; k x k
   
           
3 17 7
2 2 2 2
12 4 12 4
f) k x k ; k x k ; k x k
     
                  
3 5 5
2 2 2 2 2 2
4 6 4 4 6 4
g) k x k ; k x k ;
k x k ; k x k ;
   
           
  
            
3 10 7
10 10 10 10
2 2 3 2
9 20 25
10 5 10 10 10
2 3 3
h) k x k ; k x k ;
   
            
8 10
2 2 2 2
3 3 3 3