Posted by **Jay111** on Monday, November 24, 2008 at 11:50pm.

For x [–14,13] the function f is defined by

f(x)=(x^3)(x+6)^4

On which two intervals is the function increasing (enter intervals in ascending order)?

I got increasing intervals between [-14, -6], but can't find the other increasing interval. I believe it is [-3, 13] but I get the answer is wrong. Thanks again.

- Math -
**drwls**, Tuesday, November 25, 2008 at 12:02am
The places where the function changes from increasing to decreasing are where f'(x) = 0

f'(x) = 3x^2(x+6)^4 + 4(x+6)^3*x^3

= (x+6)^3 [7x^3 +18x^2]

I can see that becoming zero at x=0, x=-6, and x = -18/7, but not at x=-3

recheck your numbers and mine

## Answer This Question

## Related Questions

- math-calc - for x (-12, 10) the function f is defined: f(x)=x^7(x+2)^2 On which ...
- calculus - For x ∈ [−12, 10] the function f is defined by f(x) = x7(...
- calculus - For x including [–15, 13] the function f is defined by f(x)=x^7(x+4)^...
- math - x^2 - 4 What are the: Intervals on which the graph is above the x axis ...
- calculus 1 - f(x) = 3x^3 - 9x + 5 find the: 1) zeroes or undefined values 2) ...
- math - . Given the following function, f(x)=-x^2 -8x find: (a) vertex, (b) axis...
- math-calc - Consider the function f(x)= (2x+8)/(6x+3). For this function there ...
- Calculous - let f be the function defined by f(x)=12x^2/3 -4X a)find the ...
- algebra - Given the following function, find: (a) vertex (b) axis of symmetry (c...
- increasing and decreasing intervals - Have to find the intervals on which f(x...

More Related Questions