3 Find the intervals in which the function f given by
4sin
2
cos
( )
2
cos
x
x
x
x
f x
x
−
−
=
+
is (i) increasing (ii) decreasing 4 Find the intervals in which the function f given by
3
13
( )
,
0
f x
x
x
x
=
+
≠
 is
(i) increasing
(ii) decreasing