Science 122

Laboratory

COMPUTER NOTES


In a text environment, computers will often use computer notation. It will take a little getting used to, but the changes are simple to follow. Most word processors will allow the use of formatted characters. Text files and many e-mail programs do not.

Computer language uses slightly different formats for some common mathematical operations.

2.1. Exponents do not work in text documents. Instead of using exponents you will often see the carat "^" used to mean "raised to the power".

For example, R^2 is computer notation for R2 "R squared" or "R to the power 2".

2.2. Square root signs do not work well in text. Instead we use SQRT(). The expression" SQRT(4) = 2" means "the square root of four is two."

2.3. Subscripts do not work in text documents. Instead of using subscripts we use x1 and x2 to mean x "one" and x "two", and so on to mean different values of a variable we have called "x".

2.4. Equations involving multiplication will look different. The multiplication operation is the asterisk, "*". It is [shift][8] on the keyboard. Most ten-key numerical keyboards have the mathematical symbols. (Actually there are more than ten keys, but the name sticks from the old calculator days.)

2.5. Equations involving division will look different. The computer performs operations in a specific order. It will always do multiplication and division first, followed by addition and subtraction.

For example the statement "y divided by (x+1)" becomes: y /(x+1). Note how the PARENTHESES GROUP THE OPERATIONS and change their order so that "y/(x+1)" is not the same as "y/x+1". The computer will read y/x+1 as (y/x)+1.

2.6. The number "pi" is written as pi() in computer language. The symbol () is open and closed parentheses with no space between. It is sometimes approximated as 3.14 . A more precise value is 3.14159. If your calculator has a pi key is is best to use it. If not, use pi() = 3.14159. On a spreadsheet such as Excel the number pi() can be entered in a cell or a formula by typing "=pi()" (without the quotation marks).