1. Functions

2. Analytic plane x-axis y-axis origin 1 st quadrant (+,+) 2 nd quadrant (-,+) 3 rd quadrant (-,-) 4 th quadrant (+,-)

8. a b A = (a, b) denotes the set of all real numbers between a and b (a and b are excluded). A = [a, b) denotes the set of all real numbers between a and b (a is included and b is excluded). a b

9. a b A = (a, b] denotes the set of all real numbers between a and b (a is excluded and b is included).