"La mayor parte de las ideas fundamentales de la ciencia son esencialmente simples, y deben, como regla, ser expresadas en un lenguaje que cualquiera pueda comprender".
A. Einstein

## martes, 25 de octubre de 2011

### Square roots

The opposite of squaring a number is called finding the square root.
See some examples here.

A square root of a number is a value that can be multiplied by itself to give the original number.
A square root of 9 is 3, because when 3 is multiplied by itself you get 9.

What can I multiply by itself to get this?
 To help you remember think of the root of a tree: "I know the tree, but what is the root that produced it?"In this case the tree is "9", and the root is "3".

Here are some more squares and square roots:

 4 16 5 25 6 36

These are the first perfect squares:

It is easy to work out the square root of a perfect square, but it is really hard to work out other square roots.

Example: what is √10?
Well, 3 × 3 = 9 and 4 × 4 = 16, so we can guess the answer is between 3 and 4.
• Let's try 3.5: 3.5 × 3.5 = 12.25
• Let's try 3.2: 3.2 × 3.2 = 10.24
• Let's try 3.1: 3.1 × 3.1 = 9.61
• ...
Getting closer to 10, but it will take a long time to get a good answer!
 At this point, I get out my calculator and it says: 3.1622776601683793319988935444327 But the digits just go on and on, without any pattern. So even the calculator's answer is only an approximation !

The Easiest Way to Calculate a Square Root
 Use your calculator's square root button!
(And also use your common sense to make sure you have the right answer)