Section 1.1 – Interval Notation
Objectives *Review previously learned formulas. *Write things in interval notation.
Plotting points Plot the following points on the coordinate plane: (4,-3) (7,1) (-1,5) (-3,-6) Which quadrant do each of them lie in?
Quadrants
Finding the distance between two points There are three different ways that we can do this:
Method #1 This method only works when the two points share the same x-coordinate or y- coordinate. Example: Find the distance between (2,6) and (14,6)
Examples Find the distance: (-4,3) & (8,3) (2,-1) & (18,-1) (4,0) & (10,0)
Method #2 Plot the following points on the coordinate plane and find the distance: (-2,5) & (6,4)
Pythagorean Theorem The sum of the squares of the legs of a right triangle equals the square of the hypotenuse, so:
Finding the distance between two points using Pythagorean Theorem Plot the following points on the coordinate plane and find the distance: (4,2) & (-1,3)
Method #3 – Distance Formula We can use the distance formula to find the distance between any two points.
Example Using Distance Formula Find the distance between the points (-4,8) and (6,5).
Now you try… Find the distance between the two points using any method. (5,2) & (14,2) (-3,7) & (0,4) (6,8) & (-1,3) (5,5) & (2,1)
Interval Notation Interval Notation is a method for writing down a set of numbers. There are three different types of interval notation: Open Intervals Half-Open Intervals Closed Intervals
Open Intervals Write the following in interval notation: “All values of x such that x is greater than 7.” “All values of x such that x is less than -2” *We use _____________ when we are not including the number!
Half-Open Interval Write the following in interval notation: “All values of x such that x is greater than or equal to 5 and less than 21.” “All values of x such that x is less than or equal to 16 and greater than 2.” *We use ___________ when the number is included.
Closed Interval Write the following in interval notation: “All values of x that are greater than or equal to 4 and less than or equal to 6.” “All values of x that are greater than or equal to 8 and less than or equal to 14.”
More Examples… x is greater than 4 or x is less than -5. x is greater than or equal to 8 or x is less than 2. x<5 or x>10 x≤14 or x≥19
Worksheet