Ex 2.6, 1 (iii)

Transcript

Ex 2.6, 1 (iii) Draw the graphs of the following sets of lines. In each case, reflect on the role of ‘a’ and ‘b’. (iii) y = 5x, y = –5x To draw the graph, we join points which lie on the line For y = 5x Putting x = 0 y = 5 × 0 y = 0 So, x = 0, y = 0 lie on the line i.e. (0, 0) lies on the line Putting x = 2 y = 5 × 1 y = 5 So, x = 1, y = 5 lie on the line i.e. (1, 5) lies on the line For y = –5x Putting x = 0 y = –5 × 0 y = 0 So, x = 0, y = 0 lie on the line i.e. (0, 0) lies on the line Putting x = 1 y = –5 × 1 y = –5 So, x = 1, y = –5 lie on the line i.e. (1, –5) lies on the line y = 5x y = –5x Reflection on 'a' and 'b’ These two lines have the exact same level of steepness because the number 5 is the same. The only difference is the sign. y = 5x is a steep uphill climb, while y = -5x is a steep downhill drop. They look like perfect mirror reflections of each other across the y-axis!