# Interval notation for a graph?

• Oct 4th 2012, 04:58 PM
DasRabbit
Interval notation for a graph?
I've tried this about five times and keep getting it wrong. I input my attempt at an answer in the attachment below. Can someone tell me when I'm doing wrong please? This is getting frustrating. If I'm wrong, can someone please help me.
12345-1-2-3-4-5123456-1-2-3-4-5-6
• Oct 4th 2012, 06:31 PM
Prove It
Re: Interval notation for a graph?
Quote:

Originally Posted by DasRabbit
I've tried this about five times and keep getting it wrong. I input my attempt at an answer in the attachment below. Can someone tell me when I'm doing wrong please? This is getting frustrating. If I'm wrong, can someone please help me.
12345-1-2-3-4-5123456-1-2-3-4-5-6

I'm afraid you're not even close with the answers you gave. A function is increasing when it slopes upwards, and its decreasing when it slopes downwards. At turning points, it is neither increasing nor decreasing.
• Oct 4th 2012, 06:45 PM
Soroban
Re: Interval notation for a graph?
Hello, DasRabbit!

Quote:

I've tried this about five times and keep getting it wrong.

Code:

                    |                     |      *                     |               o    |           *  .  *  |      *         *    .    *|        - - * - - + - - * - - * - -             -3    |*  * 1       *            |  o                     |                     |       *            |                     |

The relative maximum is at $x = \text{-}3$
The relative minimum is at $x = \tfrac{1}{2}$

The function is increasing on: . $\left(\text{-}\infty,\,\text{-}3\right)\,\cup\,(\tfrac{1}{2},\,\infty)$

The function is decreasing on: . $\left(\text{-}3,\,\tfrac{1}{2}\right)$
• Oct 5th 2012, 09:28 AM
HallsofIvy
Re: Interval notation for a graph?
Perhaps your problem is this: a function is increasing if y increases as x increases and is decreasing if y decreases as x increases. That is, look at the graph as you go from left to right. Your answer seems as if you went from (0, 0) to the left and right.