## What really are intervals in respect to functions ? As defined they

What really are intervals in respect to functions ? As defined they are subsets of real numbers, for example, two numbers a,b belonging to R and a<b, so with that we can make out four intervals or sets with some variable x and treating a and b are inclusive or exclusive limits and also some infinite intervals :\. How does that have any utility with functions and what are these variables a and b for ? Please someone elaborate on this ?
 That means that the domain or the value the variable can take is defined from that set. Eg- If I define a set over [a,b], it means the variable involved can take its value from a to b both inclusive only. For any other number out of this set, the function does not exist.

 Quote by Akshay_Anti That means that the domain or the value the variable can take is defined from that set. Eg- If I define a set over [a,b], it means the variable involved can take its value from a to b both inclusive only. For any other number out of this set, the function does not exist.
Thanks You .