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## #1 Re: Help Me ! » A pool table » 2017-05-02 02:08:59

Does anyone have any ideas on this one?Any hints are appreciated.

## #2 Help Me ! » A pool table » 2017-05-01 00:43:52

Mario23
Replies: 3

What is the ratio between the lengths of a rectangular pool table if a ball launched from one of the sides under an angle of 45° passes through the starting point after 6 reflections?(when I say reflection I mean that the ball hits the side of the table)

## #3 Re: Help Me ! » I need help with this please » 2017-04-09 00:57:38

But, the semi-circles and the circles may be of different sizes also. The size is not specifies in the question.

I think the size doesn't matter as 3 will be needed as greg said.I don't know yet if the answer is the same for a sphere.

## #4 Re: Help Me ! » I need help with this please » 2017-04-09 00:56:11

bob bundy wrote:

???  No, still don't get it.  What's the difference between a circle and a disk?  If two semicircles meet what does it matter if they're open?

Here's my solution.

http://i.imgur.com/sXx6Z60.gif

You cannot see the original circle (it is red) because it's covered.

Bob

The  disk is the inside of the circle

## #5 Re: Help Me ! » I need help with this please » 2017-04-08 07:08:56

@greg1313 how do I extemd this to a sphere?Will I need 3 hemispheres like here?

## #6 Re: Help Me ! » I need help with this please » 2017-04-08 05:49:32

Hey.
The problem says nothing about their size,it only says that an open secircles is a semicircle without its ends.

## #7 Help Me ! » I need help with this please » 2017-04-08 03:23:53

Mario23
Replies: 12

a)How many open semicircles are needed to fully cover a circle?
b)How many open hemispheres are needed to fully cover a sphere?
It is the first time I've ever seen questions like this and I don't know how to approach them.Please help me!

## #8 Help Me ! » Infinite solutions » 2017-01-26 06:12:05

Mario23
Replies: 0

Hi guys! I need some help with this exercise I am trying to do so as to be prepared for the math olympiad:
Be n>=2 a natural number.Prove that the equation

has an infinity of solutions in N*.
My idea initially was to use mathematical induction to prove it,but then I thought that maybe it is a diophantine equation.I need some help with it

## #9 Re: Help Me ! » A peculiar inequality » 2017-01-19 18:03:15

How did you get it thickhead?

## #10 Help Me ! » A peculiar inequality » 2017-01-19 05:24:42

Mario23
Replies: 7

Be the numbers

.If
find the minimum of the sum
.
I tried to show that sum is >= than something but no luck.I tried using all the inequalities I know but I didn't use any which help,so I need your help guys

## #11 Re: Help Me ! » Need help with these equations » 2017-01-17 09:24:48

Yeah that's what I tried to do too.It seems that the equations have an infinity of solutions.I thought I was missing something
Just wondering,how did you find all those numbers above?

## #12 Re: Help Me ! » Need help with these equations » 2017-01-17 05:03:19

Oh my God that's a lot of numbers.Which are the relationships you are thinking at?

## #13 Re: Help Me ! » Need help with these equations » 2017-01-17 04:06:13

Well the only thing I did not include is that x,y and z are distinct from one another

## #14 Help Me ! » Need help with these equations » 2017-01-17 02:47:25

Mario23
Replies: 7

Hey guys,here I am with another exercise I can't solve.
Find all the triplets of distinct real numbers (x,y,z) for which:

I remember this problem as an exercise for integers.There I would use that xyz=1 but how do I do it for reals?

## #15 Re: Help Me ! » Find all the n numbers » 2017-01-14 22:21:58

They are right,I checked them

## #16 Re: Help Me ! » Find all the n numbers » 2017-01-14 06:00:57

Thank you for your help !

## #17 Re: Help Me ! » Find all the n numbers » 2017-01-12 06:42:35

Okay,I am looking forward to seeing your ideas

## #18 Re: Help Me ! » Find all the n numbers » 2017-01-12 05:12:04

My best try at proving that using that relation was that

where m is a rational number.I used then that the other frac is mq and I tried to square them,divide the ecuations etc but it is definitely not working.

## #19 Re: Help Me ! » Find all the n numbers » 2017-01-11 17:36:53

Well I don't know.There are usually more .And I don't know how to prove there aren't.

## #20 Re: Help Me ! » Find all the n numbers » 2017-01-11 08:18:42

Yes,I managed to guess it too but I don't know how to find all of them.

## #21 Help Me ! » Find all the n numbers » 2017-01-11 07:17:28

Mario23
Replies: 13

Hey! I've come across an exercise I can 't seem to solve.
Find all the n integers that satisfy :

is a rational number.
I can't see how to find them because 4n-2 can't be a perfect square and that's why I need some help on it.

## #22 Re: Help Me ! » The first 3 decimals of this number » 2017-01-04 08:32:37

Yeah,I managed to finish it from that point.Thank you all for your help!

## #24 Re: Help Me ! » The first 3 decimals of this number » 2017-01-04 02:47:48

So I should prove that

is independent of n?
EDIT:That's the only thing I can't prove so I could use a hand

## #25 Re: Help Me ! » The first 3 decimals of this number » 2017-01-03 23:06:58

Ok so from that point I applied that theorem but what should I do next?