For question#1, I think I may have got it...
So my 2nd derivative was :
But I've just noticed I can factor out a 3x so I have now:
So my critical point would be x=9/10?
Hurrah? Or no Hurrah?
Have a few questions guys
1. Test for concavity and inflection points.
**So, to find the inflection points, I know I need to apply the 2nd derivative test which I got:
From here, I set the 2nd derivative =0 which I am having a hard time with.... I think I need to factor somewhere but I don't see it (well its not obvious to me hence I am here. ) For Concavity, you just plug in numbers that are bigger or smaller than your critical # to find where its concavity correct?
And can someone help me with the concavity question?
The Second question:
2. Test the function for relative maximum and minimum.
** I applied the second derivative test again to try and find the critical points: f''(x)=24x-216
Which my textbook tells me is wrong.
As usual, TIA
Thanks, I'll plug away at the 2nd question now ( looking at it again, I think I need to apply the chain rule somewhere..). I realized that I posted this on the wrong sub forum. Can someone move this to the appropriate forum please?