## Monday, 21 November 2011

### How to find the matrix A if we known of Leontief matrix

How to find the matrix A if we known of Leontif matrix. This post is a continuation of my previous post about the Leontief inverse matrix, as well as to answer questions friend about the inverse matrix, which asks you about how to calculate the matrix technology if we known the Leontief inverse matrix.

If we let the technology matrix is a matrix A, and L is the Leontief inverse matrix.

L = (I - A) -1

then if L will be inverse again , Then will generate a matrix (I - A), illustrated by below equation
L-1 = (I - A) -1 = ((I - A) -1) -1 = (I - A)
then the matrix A can be calculated:
I - A = (I - A)
-A = (I - A)-I
A = absolute((I - A)-I)

Based on equation of the matrix above, then by using excel the above equation can be calculated with the following guidelines:

1. Create a table as below

### How to calculate Leontief matrix in excel

Calculate the Leontief matrix in excel. Leontief matrix is a matrix that is the inverse of identity matrix minus matrix A. Leontief matrix is widely used in making the simulation or quantitative input-output analysis. In mathematical equations used to define the matrix Leontif are:

L = (I - A) -1

where:
L = matrix inverse Leontief
I = Identity Matrix
A = matrix A

By using Microsoft Excel, if we known a matrix A, then the Leontief inverse matrix can be calculated
to be more easily able to see the guidelines below:

1. Create a table matrix A and the identity matrix as below

### How to calculate logarithm addition and logarithm multiplication in excel

How to calculate logarithm addition and logarithm multiplication in excel. By using Microsoft Excel, in addition  to calculate logarithm reduction and log division. Can also be done multiplication and addition of logarithms. In this post the process of logarithm addition and logarithm multiplication refers to the properties of logarithms as below:

ª log a = 1
ª log 1 = 0
ª ⁿ = n log a
ª ⁿ log b = log b n • ª
log ª ª b • c = log b + log c ª
ª log b / c = ª log b - log c ª
ª ⁿ m = m log b / log b n • ª
ª a ÷ b = log b log a
ª b log log b • c • d = c log log d ª
ª b = c log log log a b c ÷

Before applying the formula logarithms , we need using syntax of logarithm in excel as :
LOG (number, base)

With:
Number is the positive real number for which you want the logarithm.
Base is the base of the logarithm. If base is omitted, it is assumed to be 10

One of the properties of logarithms to be used is
log ª ª b • c = log b + log c ª
In order to more easily implement it, can follow the following procedure:
1. Create the table below
Columns A, B, C will contain the data, with a logarithmic base and  number
Colum D and colum W will filled with logarithm formula

### How to calculate logarithm reduction and log division in excel

How to calculate logarithm reduction and log division in excel. By using Microsoft Excel, we can perform the calculation of logarithms. In this post specifically discussed about how to use a logarithmic reduction formula and the division of the logarithm.

In general, how to write formulas / functions in excel logarithms is using syntax:

LOG (number, base)

with:
Number is the positive real number for which you want the logarithm.
Base is the base of the logarithm. If base is omitted, it is assumed to be 10
.

A simple example application of the reduction formula and the distribution of the logarithm can be seen below
ª log b / c = ª log b - log c ª

To calculate in Excel can follow the following procedure:

1. Create a table as below
Column A is the logarithmic base
Columns B and C is filled with data
Column D and E will filled with logaritm formula

## Tuesday, 18 October 2011

### Calculate circumference of a circle in excel

With using excel we can find circumference of a circle. If we know the radius value, diameter value or area value then we can calculate and find circumference of a circle.

There are some formula to calculate circumference of a circle in excel, is defined on below table :

With :
A = area of cirle
d = diameter of circle
C = circumference of cirles

### How to Calculate the Area of a Circle

A circle is one of the geometric shapes, sometimes we need to calculate the radius, diameter, area or circumferences of circle. With using excel we can find the radius, diameter, area or circumferences of circle  using formula below :

For example :
1. Create table below
There are 3 cell contain data .
a. Cell B5 is a radius data
If we know radius value, then we can calculate the area of circle
b. Cell B9 is a diameter data
If we know diameter value, then we can calculate the area of circle
c. Cell B13 is a circumferences data
If we know circumferences value, then we can calculate the area of circle

## Friday, 7 October 2011

### Free audio converter amr to mp3/wav, wav/mp3 to amr

Amr audio file format was first made for mobile, if the amr file to be run on a computer requires a software amr player, or can also be a way to convert audio files into mp3 format to audio files can be read on the mp3 player like winamp or windows media player.

This amr converter software now widely available on the internet with a variety of character types licence from free (freeware) or paid/commercial. Free amr converter software which can be used such as:

1. Amr player plus amr converter
This software other than as a player amr file extension, can also be used to convert amr files into mp3 (amr to mp3), or to wav (amr to wav) as well as from mp3/wav to amr
The advantages of this software is able to convert amr files into mp3, mp3 files conversion result is small enough, The weaknesses of this software can only convert audio files one by one, making it quite inconvenient if you want to convert hundreds of files amr.

To use, simply add files to the list amr player amr file using the Add File button, then highlight one file in the file list, then click the AMR to MP3 button

### Feature Specification and Limits of Microsoft Excel 2007

There are some new feature of Microsoft Excel 2007, but every feature has specification and limits, such as :

a. Worksheet and workbook specifications and limits
b. Calculation specifications and limits
c. Charting specifications and limits
d. PivotTable and PivotChart report specifications and limits
e. Shared workbook specifications and limit

For details every Specification and Limits , we can see on table below :

### Microsoft Excel Tutorials

Microsoft Excel is a powerfull spreadsheet application that can be use for calculation of dataset, create graph, make pivot tables, and customize procedure calculation using a macro programming language called Visual Basic for Applications.

Below there are some tutorials  microsoft excel 2003 and 2007 for beginner.

Introduction

### What's new in Microsoft Office Excel 2007

Microsoft Office Excel 2007 provides powerful tools and features that you can use to analyze, share, and manage your data with ease

There are some new feature in Microsoft Office Excel 2007, such as :

1. Results-oriented user interface with ribbon menu

The new results-oriented user interface makes it easy for you to work in Microsoft Office Excel. Commands and features that were often buried in complex menus and toolbars are now easier to find on task-oriented tabs that contain logical groups of commands and features. Many dialog boxes are replaced with drop-down galleries that display the available options, and descriptive tooltips or sample previews are provided to help you choose the right option.
No matter what activity you are performing in the new user interface—whether it's formatting or analyzing data—Excel presents the tools that are most useful to successfully complete that task.

2. More rows and columns, and other new limits

## Friday, 16 September 2011

### How to create horizontal navigation bar using css script (drop down menu version)

oOne of the horizontal navigation menus are created using css and html scripts that can be put on the blog is a horizontal navigation menu / dropdown menu. As the picture below:

In this tutorial we will build the navigation bar from a standard HTML and css script list.

A navigation bar is basically a list of links, so using the <ul> and <li>elements tag :

1. Step 1 (Insert css menu on template blogspot)

## Thursday, 28 July 2011

### Calculate angles using the arcsin, Arccos, arctan in excel 2007

Arcsin function is a trigonometric function that is used to calculate the inverse sinevalue, while the arccos are inverse cosine function, and atan is the inverse tangent function.
This function is an inverse function of sin, cos, tan. In general, writing formulas in Excel can be seen below

syntax:
arc sine ---> ASIN (number)
arc cosine ---> ACOS (number)
arc tan -----> ATAN (number)

Note: a number in radians domain
To display the results of the inverse sine, cosine, tangent in degrees then the formula above needs to be simplified by multiplying by 180/PI () or by combiningthe functions DEGREES

In general the writing of ASIN(), ACOS (), and ATAN() in mathematical equations can be seen below

Example:

1. Create a table below

## Monday, 16 May 2011

### Free primes number calculator (freeware)

Software primes number calculator is a freeware software can be used to calculate the prime numbers or search and generated primes numbers in any intervals. Software prime numbers is very simple and could be an alternative for users who have difficulty calculating prime numbers.

To use this software is to enter the interval value of numbers in the Input Range, and click the "calculate prime numbers" button, then the program will calculate and display the prime numbers contained in the desired interval.

There are several features such as calculating the number of prime numbers, the total number of prime numbers within a certain interval, as well as facilities to save results of primes that have been calculated.

Compatible with Windows 98, 2000 , XP, Vista and Seven

## Friday, 25 March 2011

### How to chat multi ID YM (Multi login Yahoo Messenger )

How to chat multi ID Yahoo Messenger (Yahoo Messenger Multi login). Today we will try to use a free software (freeware yahoo messenger tweaking). This software can perform some configuration on IM applications so that we can open more than one Yahoo Messenger application simultaneously in a same computer, so can chat on ym with multi login using the Yahoo ID from a different email.

There are several configuration options that are available on the software Yahoo Messenger Tweaker:
1. Enable multiple instances, to enable multiple applications can be opened simultaneously YM (yahoo messenger, multi-tasking), check this option if you want to use Multi ID Yahoo messenger
3. Enable tabs, can activate Tab YM
4. Fix (can not see what I type), can be used to improve the writing on the chat bar user to be able to appear, sometimes because of the conflict or software compatibility problems when the text chat does not appear, you can use this feature to display the article in the chat window
6. Rename titlebar, change the title titlebar
8. Clear status messages, clear the status messages

## Thursday, 13 January 2011

### Blender free software 3D content creation

Blender is the free open source 3D content creation suite.  Blender is a powerfull 3D Software for modeling - shade - animate - render - composite - interactive 3d
Blender's animations systems supports a variety of techniques and tasks, allowing the creation of complex animations.

OS Supported Platforms : Windows 2000, XP, Vista,  Mac OS X (PPC and Intel),  Linux (i386, SGI Irix 6.5, Sun Solaris 2.8 (sparc)