Maths - Set Notation for Inequalities
Pearson Edexcel Mathematics 2022
Reading set-builder notation
What does the set $\{x \colon x < 6.5\}$ describe?
All numbers that are less than $6.5$.
What does the set $\{x \colon x > -2\}$ describe?
All numbers that are greater than $-2$.
Writing inequalities as sets
How could you write the set for all numbers less than or equal to $5$?
How could you describe $-2 \le x < 6.5$ as _ one _ set?
How could you describe $-2 \le x < 6.5$ as the intersection of _ two _ sets?
Combining inequalities with set operations
How can you describe two inequalities that have been “stuck” together using set theory?
The intersection of two sets ($\cap$) for each condition.
How can you describe two inequalities that are separate and can’t be combined using set theory?
The union of two sets ($\cup$) for each condition.
What should you always do when working with multiple inequalities?
Draw a number line.