# Increasing/ Decreasing intervals

• Nov 14th 2011, 05:04 PM
habibixox
Increasing/ Decreasing intervals
For x ∈ [−12, 11] the function f is defined by

f(x) = x3(x + 6)^6
On which two intervals is the function increasing (enter intervals in ascending order)?
Find the region in which the function is positive: to
Where does the function achieve its minimum?

when i derived it i got

3x^2(x+6)^6 + 6x^3(x+6)^5
then you set it equal to zero... how do i use the algebra part now?

I tried something like this:

(x+6)^5 [3x^2(x+6)+ 6x^3]

I got all the answers now but the last....
when does it reach it's minimum?
• Nov 14th 2011, 05:38 PM
Prove It
Re: URGENT! DUE 12 AM!! Increasing/ Decreasing intervals
Quote:

Originally Posted by habibixox
For x ∈ [−12, 11] the function f is defined by

f(x) = x3(x + 6)^6
On which two intervals is the function increasing (enter intervals in ascending order)?
Find the region in which the function is positive: to
Where does the function achieve its minimum?

when i derived it i got

3x^2(x+6)^6 + 6x^3(x+6)^5
then you set it equal to zero... how do i use the algebra part now?

I tried something like this:

(x+6)^5 [3x^2(x+6)+ 6x^3]