Question

Determine the intervals on which the function is concave up and intervals on which the function is concave down.

1. f(x) = x^3.
2. f(x) = x e^(-x).
3.f(x) = x-2 sin x defined on the interval (0,3 pi).
4. f(x) = [x^2]/[x^2-1].

Answer 1

try to use the second derivitive (\[d^2y/dx^2\]

Answer 2

Then what?

Answer 3

then make it equals zero
and then find the values of (X)
and after testing them on the numbers scale you can find the concavity or the cancavity

Answer 4

try it
if it was hard i`ll explain how to do it