00:01
The function hx is given as x cubed minus 3x.
00:06
So first of all, obtain h -dash -x and h -double -dash -x.
00:10
So h -d -dash -x will be 3x2 -minex and h -dbblash x will be 6x.
00:18
For a part, we need to obtain the critical points.
00:21
Critical points are the points at which h -dash -x is 0, which says that 3x square minus 3 is 0.
00:29
3x square is 3 x square is 1 which implies x is plus minus 1 so for x equal to 1 h x will be 1 cube minus 3 into 1 which is minus 2 for x is minus 1 h x will be minus 1 cube minus 3 into minus 1 which is 2 so the critical points are the points 1 minus 2 and minus 1 2 these are the critical points to check whether these are points are relative maximum relative minima or neither we will check the sign of h double dash x so h double dash of 1 will be 6 into 1 which is 6 as it is positive it has relative minima for h double dash of minus 1 we have 6 into minus 1 which is minus 6 negative hence it is relative maximum so therefore it has a relative minima at point 1 minus 2 and relative maxima at point minus 1 2.
01:50
So this is the correct answer of a part which is option a.
01:57
For part b we need to check the interval of increasing or decreasing.
02:03
For this h -dash x function is 3x square minus 3 and it is 0 at point 1 and minus 1.
02:12
So we divide the interval into three parts first is minus infinity to minus 1 minus 1 to 1 and 1 to infinity take a test point as minus 2 0 2 so this is test point this is test interval now we'll finding the value of h -dash x so at minus 2 h -dash x will be 9 at 0 it will be minus 3 at 2 it will be 9.
02:48
So it is positive, negative and positive.
02:58
Therefore the function is increasing in the interval minus infinity minus 1 union 1 to infinity and decreasing in the interval minus 1 to 1.
03:13
For part c we need to obtain the point of inflection which occurs at h -dablish x is 0...