Thus f ′(x) = 1 2
(iii)
Let f(x) = sin–1 
1
12
4
x
x
+




+
 To find the domain of this function we need to find all
x such that 
21
1
1
1
4
x
x
+
− ≤
≤
+ Since the quantity in the middle is always positive,
we need to find all x such that 
1
2
1
1
4
x
x
+
≤
+
, i