could it be explained please when you answer something in set builder notation and when you answer something in interval notation. I think I understand the differences between them, but don't understand why there are both of them and when they are needed. Thank you.

Answer 1

So, do you just want to know the difference between builder notation and interval notation and why they are needed?

Answer 2

Set Builder Notation Examples:

{y : y > 0} The set of all y such that y is greater than 0. Any value greater than 0.
{y : y ≠ 15} The set of all y such that y is any number except 15. Any value except 15.
{y : y < 7} The set of all y such that y is any number less than 7. Any value less than 7.

Common Set Notation:

|A|, called cardinality of A, denotes the number of elements of A. For example, if A={(1,2),(3,4)}, then |A|=2. A=B if and only if they have precisely the same elements. For example, if A={4,9} and B={n2:n=2 or n=3}, then A=B.

Answer 3

yes, thank you, I know HOW to answer in each of these, I just want to know WHEN to answer in either of these. Why do we need two different ways to notate.

Answer 4

This is what I know, I don't know why we need two different ways to notate but......

(This is what I know):
In linguistics and semiotics, a notation is a system of graphics or symbols, characters and abbreviated expressions, used (for example) in artistic and scientific disciplines to represent technical facts and quantities by convention.

Answer 5

This is why we use notations. (Sorry I don't know the answer to your question.)