Surds 30Oct09

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Surds 30-Oct-09
Use surds to give the value of a square root like
v20 v20 2v5
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To write a number in surds, you need to use
square numbers. If you are not to sure about
these, here is an explanation.
Here are the first 10 square numbers 4, 9, 16,
25, 36, 49, 64, 81, 100, 121
Square numbers can be found by 2 x 2 4, 3 x 3
9, 4 x 4 16 5 x 5 25 etc.
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Write v18 in surd form First - Try to find the
largest square number that will divide into 18
without giving a remainder

Square numbers 4, 9, 16
18 4 4 r 2 No 18 9 2 Yes 9 goes 2 times
Next Write v18 as v(9 x 2)
Finally We know that the v9 3 so you write
v(9 x 2) as 3 times v2
v18 3v2
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