Thread: surds

Can't fathom this one:

Express in the form a + b(root c)

(root 3 + root 2) (root 3 - root 2)

Thanks!

Originally Posted by GAdams

Can't fathom this one:

Express in the form a + b(root c)

(root 3 + root 2) (root 3 - root 2)

Thanks!

HI



so when you express this in that form ..

a=1 , b and c are both 0 .

Originally Posted by mathaddict

HI



so when you express this in that form ..

a=1 , b and c are both 0 .

I get the 1, but thought the question was looking for integer values for b and c other than 0...because if b and c are 0, then you can't actually express as a + b root c?

Originally Posted by GAdams

I get the 1, but thought the question was looking for integer values for b and c other than 0...because if b and c are 0, then you can't actually express as a + b root c?

They can be zeroes, it still gives a real solution. The original question is multiplying a surd by it's conjugate which will always give a rational answer - it's how we rationalise the denominator.

You could say that

As long as and then it will work