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# C1 Surds rationalising the denominator q watch

1. Rationalise the denominator of √6/√6 + √3

I've multiplied the top and bottom by √6 - √3 and i'm getting 2 - 3√2/3 . The correct answer in the book is 2 - √2. Where am I going wrong?
2. (Original post by AmarRPM)
Rationalise the denominator of √6/√6 + √3

I've multiplied the top and bottom by √6 - √3 and i'm getting 2 - 3√2/3. The correct answer in the book is 2 - √2. Do I literally just divide the numerator and denominator by 3 to get 2 - √2? Because surely if I divided the numerator and denominator by 3 i'd have to divide the 2 by 3 on the numerator as well, which would result in me getting an incorrect answer.
When you rationalise, you multiply top and bottom by conjugate.

Therefore you've done it correct, try simplifying your final answer by finding a common factor on the top and bottom

2 - 3√2/3 = ?
3. (Original post by ComputerMaths97)
When you rationalise, you multiply top and bottom by conjugate.

Therefore you've done it correct, try simplifying your final answer by finding a common factor on the top and bottom

2 - 3√2/3 = ?
If I multiply the bottom by 3 I still dont seem to get the correct answer
4. (Original post by AmarRPM)
If I multiply the bottom by 3 I still dont seem to get the correct answer
No no no, your first technique was correct. I'll show you:

5. The 2 shouldn't be part of the fraction, or if it is, it should be a 6.

Can you see where your working starts to differ from mine?

Edit: still getting used to LaTeX, was too slow
6. (Original post by TLDM)
The 2 shouldn't be part of the fraction, or if it is, it should be a 6.

Can you see where your working starts to differ from mine?

Edit: still getting used to LaTeX, was too slow
(Original post by ComputerMaths97)
No no no, your first technique was correct. I'll show you:

Thanks for the replies, I can see where I went wrong now. Pretty basic errors, thanks a lot for the help!

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