f'(x)=2(1-x^2)-2(x^2+10)
find interval of increasing, decreasing,concave up and down...local max and min, inflection point

Question

dumbcow · Answer

For inflection point: find second derivative and set it equal to 0
For max and min: set f'(x) = 0 solve for x and then plug it back in to f

dumbcow · Answer

a function is concave up when f''(x) >0
concave down when f''(x) < 0

anonymous · Answer

i know this but i don't how to find the critical numbers with this function maybe my algebra is rusty...lol

dumbcow · Answer

hmm..when setting f' = 0 i get x^2 = -9/2 so there are no real solutions so the slope is never zero. is this what you get?

anonymous · Answer

yea thats what i got that why i didnt know if there was a max or min and how would i find any other solutions

anonymous · Answer

I don't think that's the right derivative.

anonymous · Answer

I just redid your derivative for f and came up with something slightly different.

anonymous · Answer

I have $-2x(2x^2 + 9)$ for f'

anonymous · Answer

hmmm...yea i don't know what i did wrong...

anonymous · Answer

You were missing a factor of x from each term. I showed all my steps.