Question

Please help me find the answer for B! Anyone?!

Answer 1

f is increasing in two intervals, and is concave downwards between the two minimum points. I would say that after the second minimum also. It would be nicer if we had a function :-(

Answer 2

hmm...

Answer 3

The increasing intervals are from the minimum until the "vertex"of that "parabola". And from the second minimum to 8.

Answer 4

I would say [1,4] U [6,8]

Answer 5

Concave downwards from [1,6]. But I am unsure about other intervals.

Answer 6

Thanks, I already tried [1,4] U [6,8] like three times, but I got it wrong...even I tried to change the signs of the brackets ( ) and [ ] not sure either

Answer 7

Maybe [1,2) U (2,4] U [6,8]

Answer 8

Still wrong, but I really appreciate your help big time!

Answer 9

Ok, hang on, I will re-think this over. And I didn't help, since I keep getting it wrong, haha.

Answer 10

Have you tried None? Now I realized that that graph is f'(x).

Answer 11

yes :)

Answer 12

And I make a special mention to None, since it appears that you entered none :-)

Answer 13

But no luck hehe

Answer 14

If not then there's a glitch somewhere in the system that don't allow to have the right answer hehee

Answer 15

Hmm, because if f'(x) is > 0, then the function is increasing. f' < 0 in the whole interval, that shouldn't have an increasing value, then.

Answer 16

Also, have you tried the whole interval for concave downwards?

Answer 17

Or maybe [1,4) U (4, 8]

Answer 18

Yeah, I did, and sorry but I should list all the answers I tried at the first place, i tried the
[1,4) U (4, 8], [1,4] U [6,8], None, and even [1,4) U [4,9) but none of these answer are right....

Answer 19

[0,1] U [4,6] and variations of that? :-)

Answer 20

Sorry for being so slow, just got out of an exam, so my brain is a bit fried. :-)

Answer 21

Local minima seems x = 4.

Answer 22

AHA!!!! (0,1) U (4,6) is the answer the computer allows!!!


Thanks BMP!!!!!!!!!

Really appreciate it!!!! From my side it's already 1:20AM so GOODNIGHT and THANKS SO MUCH!!!!!!

Answer 23

I should've noted it faster, haha. Had I notice that it was the f' graph, I may have been faster. Got the x = 4? Or that wasn't right?

Answer 24

That's either an inflexion point or a local minimum; so :-)

Answer 25

yeah...thanks Dude!!

Much respect!

Answer 26

Still, I am puzzled about the first one...

Answer 27

Ah, got it. The inflexion points, that is. They are the two minima there and x = 4 :-)