How do you determine the intervals where #f(x)=3x4# is concave up or down?
2 Answers
Explanation:
By definition, a function
Let
Here, we notice that the second derivative is never greater than or less than 0, which means
Neither point of inflection
Explanation:
When we want to determine if a function is concave up or concave down, we want to analyze the function's second derivatives
We have three possible scenarios:

#f''(x)>0=># Function is concave up 
#f''(x)<0=># Function is concave down 
#f''(x)=0=># Point of inflection (neither concave up or down)
We see that our second derivative of
Hope this helps!