Extra explanation: solving inequality

Introduction: Not only equations, but also inequalities are important.

Method: Solving inequality f(x)g(x)
  1. Define the function h(x)=f(x)g(x).
  2. Determine the zeros of h(x).
  3. Make a sign chart of h(x).
  4. Read in the sign chart where h(x)0.

Conclusion: The values such that h(x)0 are the same as where f(x)g(x).

Remark: Inequalities of the form f(x)>g(x), f(x)g(x) and f(x) are solved in the same way.