## Objectives

At the end of this section you should be able to Identify and sketch linear consumption functions. Identify and sketch linear savings functions. Set up simple macroeconomic models. Calculate equilibrium national income. Analyse IS and LM schedules. Macroeconomics is concerned with the analysis of economic theory and policy at a national level. In this section we focus on one particular aspect known as national income determination. We describe how to set up simple models of the national economy...

## Getting started with Maple

The second computer package that will be used in this book is Maple. This is a symbolic algebra system. It not only performs numerical calculations but also manipulates mathematical symbols. In effect, it obligingly does the mathematics for you. There are other similar packages available, such as Matlab, Derive and Mathcad, and most of the Maple examples and exercises given in this book can be tackled just as easily using these packages instead. This is not the place to show you the full power...

## Getting started with Excel

Excel is the Microsoft spreadsheet package that we shall be using in some of our worked examples. If you are already familiar with this product, you may be able to skip some, or all, of this introductory section. A spreadsheet is simply an array of boxes, or cells, into which tables of data can be inserted. This can consist of normal text, numerical data or a formula, which instructs the spreadsheet package to perform a calculation. The joy about getting the spreadsheet to perform the...

## Y

(0, 0) 100 200 300 400 500 600 700 (450, 0) (0, 0) 100 200 300 400 500 600 700 (450, 0) You may have encountered this difficulty when solving Practice Problem 8 in Section 8.1. If desired, we can always find the exact coordinates by treating the corresponding equations as a pair of simultaneous equations and solving them algebraically. The variable x can be eliminated by multiplying equation (2) by 30 and subtracting from (1) to get Equation (3) gives y 150 and if this value is substituted into...

## ExampleEXCEL

Consider the supply and demand equations (a) Assuming that the market is in equilibrium, write down a difference equation for price. (b) Given that P0 1, find the values of the price, Pt for t 1, 2, , 10 and plot a graph of Pt against t. Describe the qualitative behaviour of the time path. 12 - Pt P 4 which rearranges to give Notice that this difference equation is not of the form considered in this section, so we cannot obtain an explicit formula for Pt in terms of t. (b) We are given that P0...