Find the intervals in which the function f given by f (x) = 2x2 – 3x is

(a) strictly increasing (b) strictly decreasing


(a) It is given that function f(x) = 2x2 – 3x


f’(x) = 4x – 3


If f’(x) = 0, then we get,



So, the points divides the real line into two disjoint intervals, and



So, in interval, f’(x) = 4x -3 >0


Therefore, the given function (f) is strictly increasing in interval.


(b) It is given that function f(x) = 2x2 – 3x


f’(x) = 4x – 3


If f’(x) = 0, then we get,



So, the points divides the real line into two disjoint intervals, and



So, in interval f’(x) = 4x -3 < 0


Therefore, the given function (f) is strictly decreasing in interval.


4
1