# Functions and Graphs - Domains and Ranges

• Apr 21st 2009, 05:18 PM
dempc
Functions and Graphs - Domains and Ranges
Could someone please help me with a couple of muliple choice questions. I have attached a document with screenshots of the questions. They should be fairly easy for someone who knows what they are doing.

Please post a full solution if you have time.

Thanks!!

DEMPC
• Apr 21st 2009, 07:07 PM
IAmLegendToo
I won't do them all, but I'll explain the first 2.

Domain is the value of all possible y values. Range is possible x values.

Looking at the first graph and equation, it's asking only for domain. So we pay attention only to the y values.

Simply look at the graph. Are there any numbers that y can not be? Yes. The graph starts with a y value equal to 1. But, there are NO y values below it. Are there any values above 1 that y can't be? No. So the domain is simply ALL REAL NUMBERS greater than or equal to 1.

Second graph. It's asking for BOTH domain and range. So we need to account for both values.

The equation is a radical, so everything inside of it must be greater than or equal to 0. So, find which value for x makes it 0, in this case, set y to 0. x= -1/2. Since, 2(-1/2) + 1 = -1 + 1 = 0. So your range is all real numbers greater than or equal to -1/2.

For domain, just look at graph really. The smallest possible y value is 0, and all values above are acceptable answers, so domain is simply all real numbers from 0 to infinite or all real numbers greater than or equal to 0.

So for question 1 (assuming answers are in order a-d), the answer is B.
Question 2, part 1 is B, part 2 is C.

You should be able to do the rest.
• Apr 21st 2009, 07:40 PM
dempc
this was perfect... thanks!!