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# C4 Binomial Expansion Help? Watch

1. Show that (1+(2/x))^-1= x/(x+2)= (x/2)(1+(x/2))^-1

I managed to show the first part, but I'm not show how to use x/(x+2) to get to the second part, so please could you show me how this is done? Thanks in advance :')
2. (Original post by couruthim)
Show that (1+(2/x))^-1= x/(x+2)= (x/2)(1+(x/2))^-1

I managed to show the first part, but I'm not show how to use x/(x+2) to get to the second part, so please could you show me how this is done? Thanks in advance :')
post a pic so I can see what you've done / type in latex.

Inb4 Zacken saves you.
3. (Original post by couruthim)
Show that (1+(2/x))^-1= x/(x+2)= (x/2)(1+(x/2))^-1

I managed to show the first part, but I'm not show how to use x/(x+2) to get to the second part, so please could you show me how this is done? Thanks in advance :'
maybe you said this?
??
4. (Original post by poundsoffat)
maybe you said this?
??
Yeah, that's what I meant- sorry, I can't take a photo and don't have maths software so couldn't write it in the format shown
5. (Original post by couruthim)
Show that (1+(2/x))^-1= x/(x+2)= (x/2)(1+(x/2))^-1

I managed to show the first part, but I'm not show how to use x/(x+2) to get to the second part, so please could you show me how this is done? Thanks in advance :'
From divide top and bottom by 2 to get: which you can re-write using index notation to get the required result.
6. (Original post by couruthim)
Yeah, that's what I meant- sorry, I can't take a photo and don't have maths software so couldn't write it in the format shown
Don't worry about it, what you'd written previous was completely unambiguous. The other users are making a fuss about nothing.
7. (Original post by Zacken)
From divide top and bottom by 2 to get: which you can re-write using index notation to get the required result.
Thank you! I can't believe I didn't realise that all this time- I was trying to get it by multiplying both top and bottom by two, which obviously didn't work...
8. (Original post by couruthim)
Thank you! I can't believe I didn't realise that all this time- I was trying to get it by multiplying both top and bottom by two, which obviously didn't work...
No worries.

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