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#251 Re: Help Me ! » Is there such a function? » 2014-11-12 03:31:05

Smallest means exactly what you think it would mean. I don't think there is any ambiguity there.

Well, every periodic function has infinitely many periods.

#252 Re: Help Me ! » Is there such a function? » 2014-11-12 02:41:03

Hm, but that function would not be periodic.

#253 Re: Help Me ! » Is there such a function? » 2014-11-11 22:35:16

Well, as it was shown that no function can have uncountable extrema, the Weierstrass function cannot have uncountable extrema.

Fixed post 59:

anonimnystefy wrote:

Speaking of which, here is a question.

Does every non-constant periodic function have a smallest positive period?

#254 Re: Help Me ! » Is there such a function? » 2014-11-11 21:01:18

It is not periodic, so it does not have a period.

#255 Re: Help Me ! » Is there such a function? » 2014-11-11 19:04:26

Speaking of which, here is a question.

Does every non-constant periodic function have a smallest positive period?

#256 Re: Help Me ! » Is there such a function? » 2014-11-11 02:33:20

Well, each of those intervals has rational endpoints, so there are certainly countably many.

#257 Re: Help Me ! » Is there such a function? » 2014-11-11 02:04:02

It's more likely in Serbian, but that's not important. The book is in English.

#259 Re: Help Me ! » Is there such a function? » 2014-11-10 08:18:20

I asked a professor today about this problem and also found out the answer to your question.

It's needed to be shown that each of those extreme points can be isolated inside an interval so that no two intervals intersect.

#260 Re: Help Me ! » Is there such a function? » 2014-11-09 05:16:18

I don't think there are uncountably many peaks, but I'm not sure.

#261 Re: Help Me ! » Is there such a function? » 2014-11-09 04:46:38

Actually, the answer is that it does not exist, but I don't know how to prove that.

#262 Re: Help Me ! » Is there such a function? » 2014-11-08 21:13:59

It is not. It has countably many such points.

#263 Re: Help Me ! » Is there such a function? » 2014-11-08 13:25:58

Strict, not strictly.

E.g. point x is a strict local maximum of the function f if there is a neighbourhood of x such that for each point y in that neighbourhood, f(y)<f(x).

#264 Re: Help Me ! » Is there such a function? » 2014-11-08 13:04:28

2) Is there a function with uncountably many strict extremal points?

#265 Re: Help Me ! » Limits » 2014-11-08 03:15:51

Are you sure? You need to multiply both the denominator and the numerator by that.

#267 Re: Help Me ! » Limits » 2014-11-08 02:12:29

I was referring to the tea kettle principle. It does not apply here.

You can "rationalise" both the denominator and the numerator.

#268 Re: Help Me ! » Limits » 2014-11-08 02:02:01

That principle does not apply here.

#269 Re: Help Me ! » Limits » 2014-11-08 01:49:30

I am getting 3/2.

L'Hopital is not needed here.

#271 Re: Help Me ! » Limits » 2014-11-08 00:26:24

Still, the right side cannot contain y, then.

#272 Re: Help Me ! » Limits » 2014-11-07 23:25:20

Because the left side does not have x at all. Should the limit operator be on the other side?

#273 Re: Help Me ! » Limits » 2014-11-07 13:21:13

bobbym wrote:

Hi;

Is this the question?

Prove:

That does not make sense.

#274 Re: Help Me ! » Permutations » 2014-11-07 12:59:16

bobbym wrote:

You are slowly morphing into a math type and therefore think that you need lots of set theory.

Math types need topology to function properly.

#275 Re: Help Me ! » tedious fractions » 2014-11-03 11:32:29

it seems like the numbers 1, 2 and 3 are going periodically upwards from left to right.

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