Syntax of if-function in excel

IF function:

The IF function is one of the most popular and useful functions in Excel. You use the IF function to ask Excel to test a condition and to return one value if the condition is met, and another value if the condition is not met.

Excel IF function - syntax:

The IF function is one of Excel's logical functions that evaluates a certain condition and returns the value you specify if the condition is TRUE, and another value if the condition is FALSE.

The syntax for Excel IF is as follows:

IF(logical_test, [value_if_true], [value_if_false])

Uses and working of excel

MICROSOFT EXCEL: Microsoft Excel provides a grid interface to organize nearly any type of information.  The power of Excel lies in it's flexibility to define the layout and structure of the information you want to manage.  Basic tasks require no special training, and Excel allows you to work with text, numbers, and date information in a relatively open and unstructured way.  Nearly 30 years after it's initial introduction, Excel remains the worlds leading spreadsheet software. This brief article provides an introduction to Microsoft Excel, major uses, and key features every Excel user should be aware of. Major Uses for Excel Excel is used widely in any financially-related activity.  The ability to create new spreadsheets where users can define custom formulas to calculate anything from a simple quarterly forecast to a full corporate annual report makes Excel highly appealing.  Excel is also used widely for common information organization and tracking like a list of sales leads, project status reports, contact lists, and invoicing.  Finally, Excel is a useful tool for scientific and statistical analysis with large data sets.  Excel's statistical formulas and graphing can help researches perform variance analysis, chi-square testing, and chart complex data.

 How Excel Works

An Excel document is called a Workbook.  A workbook always has at least one Worksheet.  Workseets are the grid where you can store and calculate data.  You can have many worksheets stored inside a workbook, each with a unique worksheet name.

Worksheets are laid out in columns (vertical) and rows (horizontal).  The intersection of any given row and column is a cell.  Cells are really where you enter any information.  A cell will accept a large amount of text, or you can enter a date, number, or formula.  Each cell can be formatted individually with distinct border, background color, and font color/size/type. 

Parts of CPU

Components of CPU:

A typical CPU has a number of components. The first is the arithmetic logic unit (ALU), which performs simple arithmetic and logical operations. Second is the control unit (CU), which manages the various components of the computer. It reads and interprets instructions from memory and transforms them into a series of signals to activate other parts of the computer. The control unit calls upon the arithmetic logic unit to perform the necessary calculations.

Third is the cache, which serves as high-speed memory where instructions can be copied to and retrieved. Early CPUs consisted of many separate components, but since the 1970s, they have been constructed as a single integrated unit called a microprocessor. As such, a CPU is a specific type of microprocessor. The individual components of a CPU have become so integrated that you can't even recognize them from the outside. This CPU is about two inches by two inches in size.

Top-view of an Intel CPU - because it is a single integrated unit, the components are not visible from the outside

Bottom-view of an Intel CPU - the gold plated pins provide the connections to the motherboard

CPUs are located on the motherboard. Motherboards have a socket for this, which is specific for a certain type of processor. A CPU gets very hot and therefore needs its own cooling system in the form of a heat sink and/or fan.

CPU located on a motherboard with a heat sink and fan directly on top

The ALU is where the calculations occur, but how do these calculations actually get carried out? To a computer, the world consists of zeros and ones. Inside a processor, we can store zeros and ones usingtransistors. These are microscopic switches that control the flow of electricity depending on whether the switch is on or off. So the transistor contains binary information: a one if a current passes through and a zero if a current does not pass through.

Transistors are located on a very thin slice of silicon. A single silicon chip can contain thousands of transistors. A single CPU contains a large number of chips. Combined, these only cover about a square inch or so. In a modern CPU, however, that square inch can hold several hundred million transistors - the very latest high-end CPUs have over one billion! Calculations are performed by signals turning on or off different combinations of transistors. And more transistors means more calculations. You may be interested to know that the material silicon used in chips is what gave the Silicon Valley region of California its name.

Early CPUs were quite bulky and did not contain as many transistors as they do today. Chip manufacturers, such as Intel and AMD, have invested a lot of research into making everything smaller and fitting more transistors inside a single processor. So when there is a new generation of chips, it typically means they have come up with a smarter way to pack more processing power into a single CPU. The general name of the processor, such as Intel Pentium 4, Intel i7, AMD Athlon, and AMD 870, refers to the underlying architecture of the CPU. There are so many different ones that it can be hard to figure out what you really need in a new computer. The best way is to go with the latest processor type that falls within your budget.

real number system,ordering,rounding numbers

The Real Numbers

In higher standard we explored the real number system. This is a set of numbers that includes the integers or counting numbers, all the rational numbers (numbers that can be represented as a ratio of two whole numbers, such as 1/3 or 3/7) and the irrational numbers (numbers that cannot be represented as a ratio of two whole numbers, such as π, e, and sqrt(2)).

You learned about combining numbers using basic operations like addition (+), subtraction (-), multiplication (× or *) and division (/). You have also been introduced to several other mathematical functions including: exponentiation (^) -- raising something to a power -- and square root (). You may even remember some of the properties that real numbers obey:

Closure

If you operated on any two real numbers A and B with +, -, ×, or /, you get a real number.

Commutativity

A + B = B + A and A × B = B × A

Associativity

(A + B) + C = A + (B + C) and (A × B) × C = A × (B × C)

Inverse

A + -A = 0, A × (1/A) = 1

Identity

A + 0 = A, A × 1 = A

Distributivity

A × (B + C) = (A × B) + (A × C)

These properties are useful to review and keep in mind because they help you simplify more complex calculations.

Order of Operations

In chemistry, as in the other sciences, we will encounter many problems in which the solution involves a series of calculations. When doing more than one operation we need follow a set of rules regarding which calculations to do first. For example, what is the "right" answer to

3 + 2 × 6 = ?

Should we go "left to right" and just do the + first and get 30, or do we do the × first and get 15? Well, in order to avoid confusion and get the correct answer, mathematicians decided long ago that all calculations should be done in the same order. You may have learned the order of operations as being: Please Excuse My Dear Aunt Sally! where the words stand forParentheses, Exponentiation, Multiplication or Division, Addition or Subtraction.

So what is the correct answer for our problem? The order of operations would say that in the absence of parentheses, you would multiply 2×6 first, then add 3, so the result should be 15.

Rounding Numbers

Another issue we need to deal with when we perform operations is how to state the answer. For example, if we are dividing a 20 centimeter wire into 3 equal pieces, we would divide 20 by 3 to get the length of each piece. If we took the time to work this division out by hand -- ack! -- we would get

20 / 3 = 6.666666666666666666.........

The 6 repeats forever. How do we report this number? We round to some usually pre-determined number of digits or decimal places. By "digits" we mean the total number of numbers both left and right of the decimal point. By "decimal places" we specifically refer to the number of numbers to the right of the decimal point.

For comparison, let's try rounding this number to 2 decimal places -- two numbers to the right of the point. To round, look at the digit after the one of interest -- in this case the third decimal place -- and use the rule:

if the digit is 0, 1, 2, 3 or 4 round down
if the digit is 5, 6, 7, 8 or 9 round up

In our example:

6.666666666666.....
    ^              
the next digit is 6 so we round up,

giving 6.67 as the desired answer. If instead we had been asked to round the number 20/3 to 2 digits the answer would have been 6.7 (two digits, one of which is a "decimal place").

Sometimes rounding is the result of an approximation. If you had 101 or 98 meters of some wire, in each case you would have "about 100 meters."

We will round many of our answers in science because the numbers will often be reporting measurements. Numbers representing measurements are only as accurate as the device used for measuring. For example, we could use a standard meter stick marked off in centimeters to measure the length of a wire as 15 cm. If sometime later we cut the wire in pieces, reporting the size of a piece of the wire to nine or ten decimal places would not make sense. You may encounter instructions in labs or in problem sets or on exams which ask you to round a measurement or result to the "nearest cm" or "nearest mL" or "nearest second". We'll look more at these accuracy issues in the section "Numbers in Science."

One other operation which you may or may not be familiar with is often used in chemistry is absolute value . The "absolute value" of a number is sometimes used instead of the number itself. Absolute value is represented as a pair of upright lines around whatever expression or number is supposed to be treated that way. The absolute value of a number expresses its distance from zero, regardless of sign. So, the absolute value of -20 is 20, and the absolute value of 19 is 19. Basically, all numbers become positive but do not change value. Most calculators will take an absolute value, usually called abs().