Thread: Function help: How to know if domain is all real numbers

1. Function help: How to know if domain is all real numbers

In a graph, how do I know if the domain is the set of all real numbers?

2. When at every value of x (in real domain) the function is defined.

For example

f(x) = x^2

in here the function is defined et every value of 'x'.

another case

f(x) = x/{(x-2)(x-3)}

here at x=2 and x=3 , the function is not defined (division by zero). Hence the domain is all real x, except x=2 and x=3.

In a graph, around these points, the value of y will go to ±infinity.

Another example

y = (x)^(1/2)

Here when x<0, the function is undefined (complex) in real range. So the domain of the function is x ≥ 0. For this one - the graph simply does not exist in the negative domain.

3. In a graph, how do I know if the domain is the set of all real numbers?
What is the definition of domain? It will be helpful to you to look it up.

Here’s the idea in a nutshell: it’s the allowable x values. For any points on a graph, the domain consists of the x values of those points.

All lines except vertical lines, for example, have domains that are all real numbers.

4. Thanks guys. Man I am not cut out for this math stuff. I want to magor in Political Science in college, so you could imagine, I'm not very good with numbers.

I'm trying my best to pass this course.

5. Originally Posted by ECD Hollis
I want to magor in Political Science in college, ..... I'm not very good with numbers
You would need to understand poll-statistics - otherwise you won't be able to change your "stance" fast enough.....

6. [quote=Subhotosh Khan]
Originally Posted by "ECD Hollis":1aymvmml
I want to magor in Political Science in college, ..... I'm not very good with numbers
You would need to understand poll-statistics - otherwise you won't be able to change your "stance" fast enough.....[/quote:1aymvmml]

Stance? Oh, I think I get you.

7. Originally Posted by ECD Hollis
Man I am not cut out for this math stuff. I want to magor in Political Science in college, so you could imagine, I'm not very good with numbers.
Any decent program in political science program today contains a good bit of mathematics. Along with probability and statistics, game theory is important component of graduate study as well as rational decision theory.

8. Originally Posted by pka
Originally Posted by ECD Hollis
Man I am not cut out for this math stuff. I want to magor in Political Science in college, so you could imagine, I'm not very good with numbers.
Any decent program in political science program today contains a good bit of mathematics. Along with probability and statistics, game theory is important component of graduate study as well as rational decision theory.
Probability and Statistics is an area I think I will do okay in. It's Algebra and Advanced Mathematics that gives me a hard time. It's like my mind doesn't work like that.

Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•