Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Please Help! Find the second derivative of f(x) = x3 + x4 and its sign chart. Which of the following is not true about f?
Find the second derivative of f(x) = x^3 + x^4 and its sign chart. Which of the following is not true about f? I know the second derivative is 12x^2+6x but i am a little confused because it asks about f not f'.
A) f is concave down on (-1/2, 0)
B) f is concave up on (-∞, -1/2) U (0, ∞)
C) f is concave up on (-1/2, 0)
D) f has inflection points at x=-1/2 and x= 0.
E) All are not true.
1 Answer
- az_lenderLv 75 days ago
I agree that f"(x) = 12x^2 + 6x.
This expression will be 0 when x is 0 or -1/2.
So on (0,infinity) f is concave up; on (-1/2,0) it's concave down; on (-infinity,-1/2) concave up.
A is true.
B is true.
C is false.
D is true.
E is false.