# A calculus of the absurd

##### 4.3.1 Introduction

A quadratic is an equation in the form

$$y = ax^2 + bx + c$$

$$y = x^2$$
Note that “$$\cdot$$” is the same as “$$\times$$”.
We can find the value of this at different points - for example, when $$x=1$$, then $$y=1$$, when $$x=4$$ then $$y=4\cdot 4=16$$ and when $$x=3.123$$ then $$y=3.123\cdot 3.123=9.753129$$.
We can also plot them on a graph. For example, the quadratic $$y=x^2$$ looks like