Posted by **claire** on Wednesday, June 4, 2008 at 5:03pm.

i'm having a lot of trouble figuring out when to use a closed or an open interval.

do i use infinity in every question where both numbers are not defined?

insight?

thanks/

- linear inequalities. -
**drwls**, Wednesday, June 4, 2008 at 6:03pm
If no lower or upper or lower limit of an interval is specified, assume it is infinity (+ or -)

- linear inequalities. -
**Calc**, Wednesday, June 4, 2008 at 6:12pm
Use an open when the sign is NOT including the anwser. Use a closed when the sign DOES include the answer.

Infinity is used when you have PARAELL lines.

- linear inequalities. -
**Anonymous**, Wednesday, June 4, 2008 at 6:23pm
how can i tell if something is included or not?

the answers i'm getting are like:

z>-3

which is the correct answer. but when i go to graph it in the computer, i always click the wrong representation of interval notation.

## Answer this Question

## Related Questions

- Math - Can someone explain to me.... when you are graphing number sets.... when ...
- Precal - Please help. I'm having a lot of trouble with solving inequalities and...
- algebra2-imaginary numbers - You can add or subtract complex numbers by treating...
- calculus - The top and bottom margins of a paster are each 6 cm and the side ...
- Algebra - Im having a hard time figuring out this problem: Use the function, y...
- Please check my Caclulus - 1. Find all intervals on which the graph of y=(x^2+1...
- Algebra - I know what the answer is just not how to exopress it. Can someone ...
- Algebra - I know what the answer is just not how to exopress it. Can someone ...
- Algebra I - I'm stuck on this problem please help me find the range of this ...
- math: real numbers - The statement below is false. Correct it by changing two ...