### Article of the week… Quadratic Equation

A quadratic equation is any equation in the form

ax2 + bx + c = 0,      where a, b, c ∈ ℝ and a≠0.

The important part is the ax2. Every quadratic equation has to have this term and a ≠ 0. Because if a = 0 then we can simplify the equation to bx + c = 0 and that’s actually a linear equation. The a, b and c are real numbers and they are usually called quadratic coefficient, linear coefficient and constant, respectively.

…and you can read the rest on the dedicated page.

### Other sources

If you haven’t found answers to your questions on this web, you can try other sources. When writing this web I usually draw knowledge from these websites or books:

• Khan Academy – there are infinite amount of high quality videos about mathematics. It’s kind of funny to hear the story how the Khan Academy has been founded, see Khan’s presentation on TEDx.
• Precalculus: With Unit Circle Trigonometry – this is a fantastic book. David Cohen knows his topic and can explain it well. And there are colorful pictures too! What more would you possible want from a math textbook?
• Calculus from Michael Spivak. As far as I know this is one of the most famous book about calculus ever written. If not the most famous.
• Wikipedia – I know, everyone knows Wikipedie so surprise here. Nevertheless is you want to know something about mathematics, it’s unlikely that you don’t find the answer on Wikipedia.

### Site map

Just choose an article and read it!