Show that 
.
We have to prove, 
.
LHS, 
[ Since, 
, 
]
= 
[ Since, 
]
= 
= 
= 
[ Since, 
]
= 
= 
= 
= 
[ Since, 
]
= 
= 
= RHS
Hence Proved.
6
Show that .
We have to prove, .
LHS, [ Since, , ]
= [ Since, ]
=
=
= [ Since, ]
=
= =
=
[ Since, ]
=
= = RHS
Hence Proved.