Posted by **Cris** on Saturday, September 17, 2011 at 9:02pm.

I'm trying to finish up my pre-cal homework and I am stuck on 2 problems...

***determine the intervals over which the function is increasing, decreasing, or constant***

32. f(x)=x^2-4x

33. f(x)=√x^2-1 (that's square root of x^2-1)

thank you so much for the help =)

- Calculus -
**Steve**, Wednesday, September 21, 2011 at 4:24pm
Hmmm. Since this is pre-cal, are you allowed to use derivatives? Assuming yes, then we have

32. f' = 2x-4

f' <0 for x<2 so f is decreasing on (-oo,2)

f' > 0 for x>2, so f is increasing on (2,+oo)

f' = 0 at x=2, so f is not increasing or decreasing there.

33. f' = x/sqrt(x^2-1)

f is undefined for -1 <= x <= 1

f' > 0 for x > 1 so f is increasing on (1,+oo)

f' < 0 for x < -1 so f is decreasing on (-oo,-1)

Use a graphing tool to verify this visually.

## Answer This Question

## Related Questions

- Pre-Calculus - I'm trying to finish up my pre-cal homework and I am stuck on 2 ...
- Pre-Calculus - I'm trying to finish up my pre-cal homework and I am stuck on 2 ...
- Math - determine the intervals over which the function is increasing, decreasing...
- pre cal - Determine the intervals on which the function is increasing, ...
- Pre-Calculus - Determine the open intervals on which the function is increasing...
- Pre-Calculus - Hi! I need help with these two. Here's the link for both pictures...
- calculus - Specify the region over which the following function f(x) is ...
- Calculus - find the intervals where the function is increasing and the intervals...
- Calculus - Consider the function f(x) = x - lnx. Find the intervals on which f(x...
- calculus - find the intervals on which the function is increasing, decreasing, ...

More Related Questions