Encountering Problems with Near Vision after 40. If you have never needed eyeglasses or contact lenses to correct distance vision, then experiencing near vision problems after age 40 can be concerning and frustrating. You may feel like you've abruptly lost the ability to read the newspaper or see the cell phone numbers.
A system of symbols used to represent special things. Example: In mathematical notation â means infinity.
Interval Notation. A notation for representing an interval as a pair of numbers. The numbers are the endpoints of the interval. Parentheses and/or brackets are used to show whether the endpoints are excluded or included. For example, [3, 8) is the interval of real numbers between 3 and 8, including 3 and excluding 8. Note: Many authors use reversed brackets instead of parentheses.