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# Surds watch

1. Rationalise the denominator

(√(a+1)-√a)
(√(a+1)+√a)

2. (Original post by Nasir.)
Rationalise the denominator

(√(a+1)-√a)
(√(a+1)+√a)

you need to multiply the fraction by

(√(a+1)-√a)
(√(a+1)-√a)

then simplify
3. Use

What could you multiply by that would remove surds from the denominator?
4. (Original post by Tbarker1)
you need to multiply the fraction by

(√(a+1)-√a)
(√(a+1)-√a)

then simplify
I did. Its all gone messy.
5. (Original post by RogerOxon)
Use

What could you multiply by that would remove surds from the denominator?
By the surds themselves?
6. I have tried several times, I don't know where I am going wrong how do you multiply three terms with another three terms.
7. (Original post by Nasir.)
By the surds themselves?
I've corrected the TeX in my post now - the Android app is really nasty.

You've been given the next step by Tbarker1. Note that

The denominator is of the form , so if you multiply by (which is 1, when a and b aren't equal), it'll reduce the denominator to , removing the surds.
8. (Original post by RogerOxon)
I've corrected the TeX in my post now - the Android app is really nasty.

You've been given the next step by Tbarker1. Note that
You might initially find it simpler to rewrite the equation using and - it'd save writing square roots all over the place, until you get to the stage where you can simplify further. Otherwise, I prefer using a half power rather than a square root sign - IMO, it's less messy.
9. in general usually, the goal is to try to make a difference of two squares on the denominator. to cancel out the surds
10. (Original post by Nasir.)
I did. Its all gone messy.
Try entering the equation into symbolab (a website). It'll give you all the steps and the solution.
11. Its still gone messy. It's fine, I am going to take a rest and do the question tomorrow, maybe convert the roots into indices instead and have a go.
12. Not getting it. Sorry.
13. what don't you get?
14. (Original post by Nasir.)
I have tried several times, I don't know where I am going wrong how do you multiply three terms with another three terms.
What are the three terms? Tbarker1 has posted a correct solution, although I wouldn't have written it slightly differently, as
15. (Original post by Tbarker1)
......
Please edit your post - it is against the rules to post a solution
16. (Original post by RogerOxon)
Does this help? ...

17. (Original post by Muttley79)
Rules are for the obeyance of fools and ..

To be fair, a complete solution had already been posted and, after lots of hints / direction, the OP was still not getting anywhere.
18. IMO this thread would have gone a lot better if someone asked the OP to post their working.
19. (Original post by Notnek)
IMO this thread would have gone a lot better if someone asked the OP to post their working.
Exactly!
20. (Original post by RogerOxon)
Does this help?

Let:

So,

I understand the xy format but I don't understand how it came to this way. See my working please and let me know where I am going. Many thanks

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