If 
, show that 
.
To show: 
Differentiating with respect to x
= 
= 
Now,
LHS = 
LHS = 
) 
LHS = 
+ 
LHS = 2
∴ LHS = RHS
1
If , show that .
To show:
Differentiating with respect to x
= =
Now,
LHS =
LHS = )
LHS = +
LHS = 2
∴ LHS = RHS