# differential equation

#### A Legacy 3D Octal Planetary Model

This is an older model of planetary motion in 3D containing eight planets. A video preview can be watched here. [sociallocker][/sociallocker]

#### Casual Introduction to Numerical Methods – spring-mass-damper system model – part#5

In this tutorial, most of the calculations for the numerical simulation a SMD (spring-mas-damper) system will be consolidated into a single formula, the coordinate formula. In this case, in order to calculate the coordinate at the end of a any time step, we will need just the coordinates from the previous two time steps and of course the input parameters (constants). These input parameters are: mass, damping ratio, spring constant and time…

#### Casual Introduction to Numerical Methods – spring-mass-damper system model – part#4

This tutorial explains the principles to generating animation for the spring-mass-damper system analyzed in the previous presentations. [sociallocker][/sociallocker]

#### Casual Introduction to Numerical Methods – a spring-mass-damper system model – part#3

Here is the third part of a tutorial in both elementary dynamics and numerical methods. It is written at a basic level and it shows you how to set up a dynamic model for numerical solving of simple differential equations. The dynamic model makes use of an infinite loop, which make the calculations advance in time. Instead of a large table with formulas, this time we have a small number of…

#### Casual Introduction to Numerical Methods – a spring-mass-damper system model – part#2

Here is the second part of a tutorial in both elementary dynamics and numerical methods. It is written at a basic level and it shows you how to solve a system of difference equations in an Excel table. It also starts to explain how to animate the model. [sociallocker][/sociallocker]

#### Casual Introduction to Numerical Methods – a spring-mass-damper system model – part#1

Here is the first part of a casual tutorial in both elementary dynamics and numerical methods. It is written at a very basic level and it shows you how to solve a system of difference equations with a pencil and a paper and perhaps a pocket calculator to speed things up.

#### 3-Body Planetary System with Options

Here is a 3-body system with 3D graphics. I made it about 2 years ago but I’ve been updating it lately. This model works at about 30 frames/second in Excel 2003 on a modern PC. In Excel 2007 it will run 10-15 times slower. I know 2010 is a lot faster than 2007. I’ve just bought a legit copy for 50$ but I didn’t have a chance to install it yet. I need to add few more features….