Question

Find the second derivative if f(x)=x^(1/3)*(x-4)

Answer 1

probably easier to start with
\[f(x)=x^{\frac{4}{3}}-4x^{\frac{1}{3}}\] and use the power rule twice

Answer 2

I actually missed all of this unit due to migraines so I'd really like to know the power rule!

Answer 3

So would f''(x)= 4/9(x)^-(2/3) - (8/9)x^(-5/3)? And how do I determine concavity from that?

Answer 4

look at this file

Answer 5

Awesome! Thanks! How do I determine Concavity from that?

Answer 6

Set the f''(x) sign now

Answer 7

Confused by what you mean by that.

Answer 8

find the sign of f''(x)

Answer 9

It would be positive correct?

Answer 10

Ohhhhhhhhhhh. You used the zeros of the second derivative correct?