# intervals of increasing/ decreasing

• Aug 16th 2009, 06:15 PM
yoman360
intervals of increasing/ decreasing
for $f(x) = x^{1/3}$
increasing: (-∞, ∞)
Decreasing: ?
for decreasing i think its none. idk
• Aug 16th 2009, 06:21 PM
pickslides

Did you mean $y=x^{\frac{1}{3}}$ ?

It will be increasing on $\frac{dy}{dx}>0$ and decreasing on $\frac{dy}{dx}<0$
• Aug 16th 2009, 06:55 PM
yoman360
Quote:

Originally Posted by pickslides

Did you mean $y=x^{\frac{1}{3}}$ ?

It will be increasing on $\frac{dy}{dx}>0$ and decreasing on $\frac{dy}{dx}<0$

I haven't learned that dy/dx stuff yet so that doesn't make sense to me right now. And yes its $f(x)= x^{1/3}$
• Aug 16th 2009, 09:22 PM
pickslides
Quote:

Originally Posted by yoman360
for $f(x) = x^{1/3}$
increasing: (-∞, ∞)

This is correct therefore it cannot be decreasing.