Thursday, July 15, 2010

Surds

Let us learn something on surds today.

Surds are numbers left in 'square root form' (or 'cube root form' etc). They are therefore irrational numbers. The reason we leave them as surds is because in decimal form they would go on forever and so this is a very clumsy way of writing them. Surd can be written as n√a where n is the order of surd and a is an irrational number. The order of surd can be of any number.

Below is the example of Surd

√60

In the above example 60 is a surd of the second order.
-->Addition and Subtraction of Surds:
Adding and subtracting surds are simple- however we need the numbers being square rooted (or cube rooted etc) to be the same.

Below is one example showing how to subtract surds.
-->
7 - 7 = 2Ö7.

Below is one example showing how to add surds.

-->
5
Ö2 + 8Ö2 = 13Ö2 Note:
-->5Ö2 + 3Ö3 cannot be manipulated because the surds are different (one is -->Ö2 and one is -->Ö3).

For more help on how to do surds click here

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