Welcome to Economics Express - a series of short books to help you: * take exams with confidence * prepare and deliver successful assignments * understand quickly * revise and prepare effectively. As you embark on your economic journey, this series of books will be your helpful companion. They are not meant to replace your lectures, textbooks, seminars or any other sources suggested by your lecturers. Rather, as you come to an exam or an assignment, they will help you to revise and prepare effectively. Whatever form your assessment might take, each book in the series will help you to build up the skills and knowledge you will need to maximise your performance. Each topic-based chapter will outline the key information and analysis, provide sample questions with responses, and give you the assessment advice and exam tips you will need to produce effective assessments based on these core topics. A companion website provides supporting resources for self testing, assessment, exam practice and answers to questions in the book. Ian Jacques was formerly a senior lecturer at Coventry University. He has considerable experience teaching mathematical methods to students studying economics, business and accounting.