Sets.

Artful_Badger

How would you write the following in property format ?

{1,1/2,1/4,1/6,1/8,1/10.....}

This isnt homework btw, its revision but I'm confused by it. I think its a/b such that a is 1 and b is something. But what ? Cant be multiples of 2 if it thats with 1.

Artful_Badger

To clarify what I mean, I'm looking for the set of {[latex]1, \frac{1}{2}, \frac{1}{4}, \frac{1}{6}, \frac{1}{8}, \frac{1}{10},....[/latex]} expressed in its property format.

{1,2,3,4,5,6,7,8........} would be {x:x is a natural number} but I'm not sure how to phrase the first one as it cant just be multiples of 2 if the set contains 1.

TheBody

CroMagnonMan wrote: »

To clarify what I mean, I'm looking for the set of {[latex]1, \frac{1}{2}, \frac{1}{4}, \frac{1}{8}, \frac{1}{10},....[/latex]} expressed in its property format.

{1,2,3,4,5,6,7,8........} would be {x:x is a natural number} but I'm not sure how to phrase the first one as it cant just be multiples of 2 if the set contains 1.

Oh now I see. I deleted my post as I had that stupid error you pointed out. That's what you get for not paying enough attention to what you are doing! I'm having a brain freeze. That 1 is a pain and I gotta so. I'll have a think about it and get back to ya if nobody gets there before me.

Artful_Badger

Another post appeared and disappeared. It has to be multiples of 2 though right ? And the only way you can get 1 from a multiple of 2 is 2(1/2). How do you phrase 1/2n where n goes from .5, 1, 2, 3, 4, 5 ...... ?

Artful_Badger

Edit: God dammit thats the third time I responded to a post that wasnt there

Brussels Sprout

CroMagnonMan wrote: »

I think its a/b such that a is 1 and b is something. But what ? Cant be multiples of 2 if it thats with 1.

2 to the power of zero = 1.

I'm not familiar with this set property terminology but adapting your other example you could come up with:

{1/(2^(x-1)):x is a natural number}

Artful_Badger

Brussels Sprout wrote: »

2 to the power of zero = 1.

I'm not familiar with this set property terminology but adapting your other example you could come up with:

{1/(2^(x-1)):x is a natural number}

Excellent stuff. I had the same thing but in a slightly different way. I ended up with {1/2x : x € N U {1} } could also have gone with {1/2^x : x € N U {0} }. Your way is better though, no need to be adding in stuff, just x-1 to start at 0. Very nice.

Delphi91

Except that won't give ya 1/10!

Artful_Badger

Delphi91 wrote: »

Except that won't give ya 1/10!

Sure it will. 1/2(x-1) where x is 6.

Edit. Sorry you're right the powers one wont. And 1/2(x-1) wont give me 1 either will it ?

Brussels Sprout

Sorry, I only glanced at the series and read it wrong. This works:

{(1-(1/(2*(x-1))) :x is a natural number}

equivariant

Brussels Sprout wrote: »

Sorry, I only glanced at the series and read it wrong. This works:

{(1-(1/(2*(x-1))) :x is a natural number}

That doesn't work either

MathsManiac

{1/(2x) : x € (N U {1/2}) }

Brussels Sprout

equivariant wrote: »

That doesn't work either

It sure doesn't. I'm an idiot