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# surds watch

1. Hey,

I know the rules for surds, however I still don't get them.

For example-/20 =-/ 4×5 which then equals 2-/5 (this " -/" is the surd sigh seen as I don't have one my phone haha. And the example is out of my so called " revision guide")

If someone could explain this process then thank you.
2. _/ab = _/a * _/b

Do you understand this rule?
3. root(ab) = root(a)root(b)

if a or b is a square number, the function root(a) or root(b) will output an integer. if the output of root b is not an integer and the output of root a is an integer, it can be written as xroot(b) where x is the root of a.
4. Yeah I understand that rule, just not how they get a number in front of the surd

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5. Urm I kinda get that now thank you.

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Yeah I understand that rule, just not how they get a number in front of the surd

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root(20)=root(4x5)...
however, root(4x5)=root((2^2)x5)
as 4 is a square number (2^2) it can be rooted so
root(4x5)=root(4) x root(5)
=2root(5)

Hope this makes sense...
7. (Original post by Nirvana27)
root(20)=root(4x5)...
however, root(4x5)=root((2^2)x5)
as 4 is a square number (2^2) it can be rooted so
root(4x5)=root(4) x root(5)
=2root(5)

Hope this makes sense...
Oh right yes that makes sense, thank you

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Updated: October 29, 2015
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