DBoy's video: How to Understand Quadratic Functions

I need advice on how to understand quadratic functions. A U shape or dead cat bounce will look like a quadratic function, at least until it starts the second bounce. I need more realistic examples. And dead cats rarely bounce, just splat. A quadratic function takes the form A squared plus b times x plus C. The answer across all values of X usually becomes a curved line like a U. That’s called a parabola. So you at least know something. The parabola may open down or up or sideways, and it may be wide or steep, but those with a positive A usually open up while those with a negative open down. This is not nearly as deep a conversation on the topic as I was hoping to have. Every parabola is going to have a vertex or peak, and all of them are symmetrical around an axis of symmetry. That’s probably why it is called symmetrical. If you want to find the vertex, find the F equal to zero and solve for X. The F? That’s the grade I’m afraid of getting in my math class. F in this case means the answer of the function. The function of this conversation was to learn the best resources for learning about quadratic equations. I suppose eighth grade math did not do it. Some people learn that in ninth grade, others in seventh. You could try Khan Academy. It has lessons on how to solve them by square roots, common mistakes people make and how to solve them. Sold! I hate the sites that show you a complicated process and do not explain it or assume the pretty picture is enough to eliminate the need to explain. Khan Academy also has discussions on solving quadratic equations via factoring, completing squares, how to use quadratic formulas, proofs of quadratics - As if we need proof that they are frustrating. If they can teach fifth graders matrix multiplication when their parents do not even know what that means, it can teach you quadratic equations. Where do I go if Khan Academy is not enough? PurpleMath.com has good lessons on quadratic equations. That sounds like a site named by the math teacher’s four year old, when he asked what she wanted it to be. If it teaches you what you want to know, it is where you want to be.