Question

Suppose that f(x)=3x−6x+5.

Use interval notation to indicate where f(x) is concave up or down.
Concave up:
Concave down:

Answer 1

Is that supposed to be\[f(x)=3x^2-6x+5\]

Answer 2

Oops! It's suppose to be 3x-6/x+5. Sorry and thanks!

Answer 3

\[f(x)=3x−6/x+5\]
\[f'(x)=3+6/x^2\]
\[f''(x)=-12/x^3\]
\[-12/x^3>0\]
\[-1/x^3>0 \]
when x<0

\[-12/x^3<0\]
when x>0

\[f(x)=3x−6/x+5\]
is concave up on the interval \[(-\infty, 0)\]
and is concave down on the interval \[(0, \infty)\]

Answer 4

My online homework said this answer was incorrect :/

Answer 5

:( Are you sure all the information you gave me was correct?

Answer 6

Uhm Yes, I just checked it again...