## The 0.0001 Time Rate Approach, an Extended Application

In the previous post, I introduced to you the 0.0001 Time Rate approach This post is an extended application of the said technique on curvatures and radius of curvatures.

Curvature is defined (by The Facts on File Dictionary of Mathematics) as the rate of change of the slope of the tangent to a curve. For each point on a smooth curve there is a circle that has the same tangent and the same curvature at that point. The radius of this circle called the “radius of curvature”, is the reciprocal of the curvature, and its center is known as the center of curvature. If the graph of a function y=f(x) is a continuous curve, the slope of the tangent at any point is given by the derivative dy/dx and the curvature is given by

$C = \displaystyle\frac{\displaystyle\frac{d^2y}{dx^2}}{(1+(\displaystyle\frac{dy}{dx})^2)^{3/2}}$

and the radius of curvature is given by

$RC = \frac{1}{C} = \displaystyle \frac{(1+(\displaystyle \frac{dy}{dx})^2)^{3/2}}{\displaystyle \frac{d^2y}{dx^2}}$

where: $\frac{dy}{dx}$ is the derivative of $y$ with respect to $x$ and $\frac{d^2x}{dx^2}$  is the second derivative of y with respect to x or in simpler terms, it is the derivative of $\frac{dy}{dx}$. » Read more

## Guest Post: Derivatives and an Introduction To Calculus

by Shaun Klassen

One of the mathematics subjects most feared by students is the “dreaded” differential calculus subject.  Absolutely, it is more complicated than more common basic algebra that most would have studied up to this point.  And of course, to work with calculus, one must be familiar with all of the earlier concepts that build up a strong mathematical foundation, including things like algebra, trigonometry, and graphing.  However, this is not to say that calculus has to be hard, or “impossible.”  It is completely doable if you start slowly by learning the general problem solving strategies.  In this guest post, I want to introduce the main concept of differential calculus – the derivative – and I encourage you to visit my math website to find out much more information about this subject.

The name “differential calculus” is a descriptive one – it is based on differences, or changes.  More specifically, it is all about describing how one quantity changes with respect to another one, or in other words, the rate of change.  The derivative is used to express this function, but let’s examine this concept a little more closely by considering everyone’s favourite rate of change: velocity.  » Read more