Posted by Alex on .
Let F be the function defined by F(X)=12X to the 2/3 power minus 4X Find the intervals of which F is increasing? Find X & Y coordinates of all relative max. pts? Find X and Y Coordinates of all relative min pts? Find the intervals of which F is concave down? Sketch a graph of F

Calc 
Reiny,
I read your statement as
f(x) = 12x^(2/3)  4x
then
f '(x) = 8x^(1/3)  4
= 0 for max/min
8/x^(1/3) = 4
4x^(1/3) = 8
x^(1/3) = 2
x = 8
then f(8) = 12(8)^(2/3)  4(8)
= 48  32
= 16
Can you take it from here?
remember that the function is concave up when the second derivative is positive and
concave down ..... 
Calc 
Anonymous,
When the second derivative is negative