look at f" - it is always positive
so, f is always concave up
just looking at it you can see that f(0) = 0, and always goes up on each side.
THANK YOU TUTORS SO MUCH FOR YOUR HELP
Determine the intervals on which the function is concave up or concave down.
I finally understand that when f'' is greater than 0 it means concave up.
f(X) = 18x^2 + x^4
so I differentiate that to be
36x + 4x^3 that is f'
if I differentiate again I get:
f'' = 36+12x^2
it's from here that I get lost. At what intervals does it represent concave up or down? and what is my next step after getting f''?
3 answers
Right, but I am unsure what to put for intervals of concave up :/
how about (-oo,+oo) ?
3 answers