Last Sunday while coaching my A-Math students on a question on Modulus Functions, we did solving of Modulus equation which is of no big problem as long as you get the basic concept correct.

|x| = x when x >= (more than and equal to) 0 or |x| = -x when x < 0

When we came to the next part of the question which involves **Sketching of Modulus Graph**, that's where the interesting happens.

Read about the Differences between Drawing and Sketching in this post.

When question involves sketching of graph, we usually do not need **
- a table of values**.

**- axis which are evenly marked out.**

Sketching of Graph should however includes

**- critical points** (i.e x - intercept(s), y-intercept, turning point (if you are sketching a quadratic graph))

Let's take a look at the working of 2 different students:

Student A:

- Sketch the modulus graph using table of values
- Join up the points in a straight line manner

Student B:

- Sketch the modulus graph using a series of 2 other graphs

**Note the difference in the shape of the 2 graphs. **

I certainly hope that my student A is convinced that using a table of values is not recommended for drawing modulus graphs. Moreover, many questions involving modulus could be that of Trigonometry graphs! So be like student B, draw modulus graph using a transformation of a series of graphs

TYS says

In my opinion, student A diagram was wrong because he or she does not use equal scale for both x and y -axis. Thus, it has created the weird shape different from standard curve shape. However, I will agree with you in encouraging students to follow Student B's method for curve sketching.

Harry says

How to sketch the graph y = |x+2|+|x-1|?

Shivali says

How to sketch y = |x+3|+|x-6|?

Andy says

Please explain me the graph of mode x plus mode y equals 1