What is the difference between [2, infinity) and (1, infinity)?

Question

Don’t the both of them mean the same? i.e from 2 to infinity?

There was this one mcq which had both of these options. So how do yoy differentiate between the two?

 

Answer 1

When a bracket is used, you include that value in the interval

 

So the interval [2,8] is all the numbers between 2 and 8 inclusive (2 and 8 are possible values)

 

When a parentheses is used, you do not include that value in the interval

 

The interval (1,9) is all the numbers between 1 and 9 exclusive, (1 and 9 are not possible values)

 

Your question:

 

[2,infinity) means all numbers greater than or equal to 2 up to to infinity

 

(1, infinity) means all numbers greater than 1 to infinity

 

hope this helps