Download presentation

Presentation is loading. Please wait.

Published byJean Besley Modified over 2 years ago

1
Graphing straight lines The gradient-intercept form of a straight line is: y = mx + b wherem is the gradient andb is the y-intercept. If the line is not in this form, I would change it to this form. How I use this form to plot a line: Plot the y-intercept (b) Move up by the “rise” Move across by the “run” Plot the 2 nd point Join the two points to form the line. Alternate method Complete a table of values Use at least three values.

2
Example 1 Graph the line y = 2x + 1 Method 1 Plot the point (0, 1) As the gradient is 2, this is 2 / 1. Move up by 2 Move across 1 Plot the 2 nd point Join the two points to form the line. Method 2 Complete a table of values Use at least three values. y = 2x + 1 x y –11 01 3

3
Example 2 Graph the line 3x + 2y + 4 = 0 Method 1 Change to y = mx + b 3x + 2y + 4 = 0 2y = –3x – 4 y = –3x / 2 – 2 Plot the point (0, –2) Move down by 3, as the gradient is negative Move across 2 Plot the 2 nd point Join the two points to form the line. Method 2 Change to y = mx + b y = –3x / 2 – 2 Pick “nice” values for x. Multiples of 2, as the denominator is 2 x y 1–2 02 –5 –2

4
Graphing straight lines Lines parallel to the axes The line x = a is parallel to the y-axis, the y-values change but x always equals a. Example 3 Graph the line x = 3 The line y = b is parallel to the x-axis, the x-values change but y always equals b. Example 4 Graph the line y = –2

5
Does a point lie on the line? A point lies on a line if its coordinates satisfy the equation of the line. OR Substitute the point into the equation of the line; if LHS = RHS, the point lies on the line. if LHS ≠ RHS, the point is not on the line Example 6 Does the point line 3x + 2y – 22 = 0 pass through the point (4, 5)? 3(4) + 2(5) – 22 = 0 0 = 0 The line 3x+2y–22 = 0 passes through the point (4, 5). Example 5 Does the point (2, 5) lie on the line y = 3x + 1? 5 = 3(2) + 1 5 ≠ 7 (2, 5) IS NOT on the line y = 3x + 1.

6
Today’s work Yesterday’s work Exercise 10:05 Q1-4 Exercise 8:03 Q1 a, c, e…o, p, q & r, Q2 & 3 all

Similar presentations

Presentation is loading. Please wait....

OK

“Teach A Level Maths” Vol. 1: AS Core Modules

“Teach A Level Maths” Vol. 1: AS Core Modules

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on sustainable development Ppt on conservation of matter Mp ppt online form 2013 Ppt on chromosomes and chromatin related Ppt on civil engineering structures Ppt on corporate social responsibility under companies act 2013 Ppt on dna computing in security Free ppt on marketing management Ppt on seasons in india Ppt on wpi and cpi