# Course Communities

So far, we have identified resources for one-variable calculus, multivariable calculus, a first course in ordinary differential equations, and a probability course, as well as for a pseudocourse containing resources for developmental mathematics.

Check out and rate the resources, make comments, start discussions, and recommend additional resources.

## Featured Items

##### Probability Distributome Navigator

This is an interactive graphical representation of the universe of probability distributions. Users can search, explore, discover or investigate the intrinsic properties of different probability distributions and inter-distribution relations. In addition, users may utilize many of the web-based probability calculators, simulators and virtual experiments.

##### Cars, Goats, $$\pi$$ and $$e$$

This resource is an article in Mathematics Magazine (2009); it also appears in Classroom Capsules and Notes. "The author proposes two extensions of the Monte Hall problem, with solutions involving the numbers $$\pi$$ and $$e$$, respectively."

##### Lesson 31: Logarithms

The lesson begins with an application problem to motivate the necessity and use of a logarithm. The formal definition linking logs and exponents is then introduced. Exercises in writing exponential equations as logarithms follows before a calculator based method for approximating logarithmic values is discussed. The common log, i.e. logs of base $$10$$, is introduced and a procedure for solving common log equations with a calculator is presented, along with various caveats about proper syntax for the calculator.

##### Beats

This applet allows one to change the frequency of two waves between 5 and 20 Hz with a slider scale as well as classify the waves as in or out of phase. You obtain the wave motion over time. The differential equation is not shown.

##### Identifying Quadric Surfaces from a Graph

Displays a quadratic surface and provides students with practice identifying the type of surface as well as its equations. Also has optional stereographic display.

##### The Utility of Catenaries to Electric Utilities

The purpose of this demo is to illustrate how hyperbolic functions and arc length integrals are used to model hanging cables.