tailieunhanh - ENVIRONMENTAL ENGINEER’S MATHEMATICS HANDBOOK - CHAPTER 2

Hầu hết các tính toán theo yêu cầu của các kỹ sư môi trường (như với nhiều người khác) bắt đầu với những điều cơ bản, chẳng hạn như Ngoài ra, trừ, nhân, chia, và chuỗi các hoạt động. Mặc dù nhiều người trong số các hoạt động là những công cụ cơ bản trong hộp công cụ mỗi kỹ sư môi trường, sử dụng những công cụ này trên cơ sở phù hợp là rất quan trọng để duy trì sắc nét trong việc sử dụng. Các kỹ sư cần phải nắm vững các định nghĩa toán học cơ. | Chapter 2 Basic Math Operations introduction Most calculations required by environmental engineers as with many others start with the basics such as addition subtraction multiplication division and sequence of operations. Although many of the operations are fundamental tools within each environmental engineer s toolbox using these tools on a consistent basis is important in order to remain sharp in their use. Engineers should master basic math definitions and the formation of problems daily operations require calculation of percentage average simple ratio geometric dimensions threshold odor number force pressure and head as well as the use of dimensional analysis and advanced math operations. basic math terminology and definitions The following basic definitions will aid in understanding the material in this chapter. Integer or integral number a whole number. Thus 1 2 3 4 5 6 7 8 9 10 11 and 12 are the first 12 positive integers. Factor or divisor of a whole number any other whole number that exactly divides it. Thus 2 and 5 are factors of 10. Prime number a number that has no factors except itself and 1. Examples of prime numbers are 1 3 5 7 and 11. Composite number a number that has factors other than itself and 1. Examples of composite numbers are 4 6 8 9 and 12. Common factor or common divisor of two or more numbers a factor that will exactly divide each of the numbers. If this factor is the largest factor possible it is called the greatest common divisor. Thus 3 is a common divisor of 9 and 27 but 9 is the greatest common divisor of 9 and 27. Multiple of a given number a number that is exactly divisible by the given number. If a number is exactly divisible by two or more other numbers it is their common multiple. The least smallest such number is called the lowest common multiple. Thus 36 and 72 are common multiples of 12 9 and 4 however 36 is the lowest common multiple. Even number a number exactly divisible by 2. Thus 2 4 6 8 10 and 12 are even .