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If x is a real number, then its modulus, |x|, gives the size of the number. If x is already positive, nothing happens, but if x is negative, it gets made positive.

For example,

|7|=7|−4|=4

|x| is sometimes called the magnitude of x, and it is also sometimes called the absolute value of x.

In this tutorial, we will learn how to sketch functions and solve equations that involve absolute values.


The function f is defined by

f(x)=|1−x2|
  1. Find f(0),f(2) and f(4)

  2. Sketch the curve y=f(x).

  3. Solve the equation

    |1−x2|=3
  4. Solve the equation

    |1−x2|=2x