Question

need help on the attachment

Answer 1

i would say all or true. if you have a graphing calculator, just pop that in and check it.

Answer 2

I just input that answer in and they said it wrong

Answer 3

well the derivative doesn't exist at x = 0 because it would equal 2/0. so just c then maybe?

Answer 4

Trogdor, are you guessing?

Answer 5

fine then. c. the answer is only c.

Answer 6

Doubt it, since C is false.

Answer 7

then its all false. is it concave up (-infinity, infinity)?

Answer 8

The second derivative is (-2/9)x ^(-4/3)...it's concave down...

Answer 9

Since the second derivative is negative...

Answer 10

OMG! okay. thanks man. i made a horrid mistake. its all so clear now. thank you sir Blue.

Answer 11

so, all of them are false?

Answer 12

indeed.

Answer 13

I got that wrong to, so that not the right answer

Answer 14

its just b then. cuz there's no slope at 0. its concave down.

Answer 15

sorry about all this.

Answer 16

are you really sure?

Answer 17

yes. tell you're teacher its my fault.

Answer 18

Tal, you should try to understand this...rather than guessing.

Answer 19

GoBlue is he right

Answer 20

You want me to just tell you the answer? Try working it out...find the derivative, see if it's differentiable everywhere. Then test for min/max, and then find second derivative to check concavity.

Answer 21

A is false because the first derivative is (2/3)(x^(-1/3)): so at x=0, the slope would be 2/0, which is a no no
C is false because the second derivative is negative so its concave down.
B is true because it comes to 1 at x=0 from both sides.

Answer 22

Thanks for explaining the reason for the answers, and it was right

Answer 23

sorry for the inconvenience. its been a little while since i did these.

Answer 24

The real reason for B is because the first derivative changes sign from negative to positive at 0, hence local minimum. Otherwise he's right. Well done.