6
Rationalised 2023-24
 MATHEMATICS
158
Interval
Sign of 
f( )
′x
Nature of function
0, 4
π




> 0
f  is increasing
π
π
4
5
,4


< 0
f  is decreasing
π45 ,2
π




> 0
f  is increasing
EXERCISE 6 2
1 Show that the function given by f (x) = 3x + 17 is increasing on R 2