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#1 Re: Help Me ! » Word Problems: Multiplying Fractions » Today 12:20:55

Hi;

You can divide by 2 or multiply by 1 / 2. Welcome to the forum.

#2 Re: Introductions » Hi » Today 12:19:16

Hi;

Welcome to the forum.

#4 Re: Exercises » New Years Problem » Today 02:44:53

That would be a piece of luck. M exposes all my weaknesses.

#5 Re: Help Me ! » Combinatorics question about brackets » Yesterday 12:59:03

Hi;

Thanks for the link. I understand how you want to count them say for ()()(). But what is the question you are asking?

I do see the formula you are conjecturing on page 5 of that pdf.

#6 Re: Help Me ! » Combinatorics question about brackets » Yesterday 12:40:23

Hi;

I think I understand the problem now. I have notes on this bracketing problem somewhere. I am looking for them now.

#7 Re: Help Me ! » Combinatorics question about brackets » Yesterday 12:07:57

Hi;

I do not understand about R(t), L(t), can you explain further.

The numbers you are suggesting are every other Catalan number.

#8 Re: Help Me ! » Find all the n numbers » Yesterday 06:52:48

Hi;

The solutions found in post #10 are correct but I am afraid their might be more that ht method I used there is missing. I hate using reasoning in math, that is why I dislike and mistrust the whole concept of proof. Trouble is, computation although more reliable can leave you hanging.

#9 Re: Exercises » Bafflers? » 2017-01-14 15:53:00

It is very desirable to get an analytic form. Can you do that, with the same rules still applying?

#10 Re: Puzzles and Games » Next number in sequence! » 2017-01-14 10:42:10

Hi chamywak;

The number they want next is

.

Welcome to the forum.

#11 Re: Help Me ! » Find all the n numbers » 2017-01-14 10:26:23

Those were just thoughts, that might have a big hole in it.

#12 Re: Exercises » New Years Problem » 2017-01-14 02:54:06

There is undoubtedly a much shorter way to do this.

#14 Re: Exercises » Bafflers? » 2017-01-13 16:13:39

This will be the toughest baffler ever posed here.

Disclaimer: Do not try this problem and then drive or operate heavy machinery.

hrJKfUb.png

Okay, you see that side PQ is the square root of 3 and the equation of the ellipse is given below it.

The rules are rather extreme:

You may not use any CAS, that means Mathematica, Maxima, Wolfram Alpha, Maple, Matlab, Mupad, Octave, Pari, Yacas, Fricas, Magma.

You may not use any programming language, that means C, C++, Wolfram, Haskell, Basic, Pascal, Cobol, Fortran, Python or any other.

You may not use any mathematics that means calculus, group theory, algebra, trigonometry, geometry (Euclidean or any other), probability, any math theorem.

You can only use the tools of EM or you can try the force.

Okay, now for the question:

If we move P and Q along the circumference of that ellipse what is the sum of the largest area and the smallest area for triangle POQ? Of course the length of PQ must always remain constant at

A says) 2.
B says) That is not correct.
C says) 6.022 x 10^23
D says) 0
E says) I know the answer.

#15 Re: Exercises » New Years Problem » 2017-01-13 14:19:23

Yes, Length is the command that will tell you how long that list is. You can try this.

Select[Range[10000], PrimeQ[#^2 + 27] && PrimeQ[# + 3] &];
Total[%]
Length[%%]

Have a good lunch.

#16 Re: Exercises » New Years Problem » 2017-01-13 13:53:20

Hi;

For a functional approach:

Select[Range[10000], PrimeQ[#^2 + 27] && PrimeQ[# + 3] &] // Total

#17 Re: Help Me ! » Find all the n numbers » 2017-01-13 06:06:32

We can say that

Solving simultaneously:

{{x = -5, y = -3}, {x = -5, y = 3}, {x = 5, y = -3}, {x = 5, y = 3}}

Are the only 4 solutions and they all give n = 13.

#19 Re: Help Me ! » Sandwich theorem » 2017-01-13 05:57:38

Since the limit of -x^2 as x approaches 0 is 0 and the limit of x^2 as x approaches 0 is 0 and

stays between them, the limit of it as x approaches 0 is also 0.

Intuitively we can understand by the following drawing that Mathegocart provided:

6MwTsXr.png

If your function the green line always stays between the red and the blue line, then as the red and the blue line get closer together the green line gets sandwiched in between.

#20 Re: Help Me ! » Find all the n numbers » 2017-01-12 05:57:59

Some ideas that I am working on seem to validate my view in post #4. 13 seems to be the only solution.

#21 Re: Help Me ! » Sandwich theorem » 2017-01-12 05:00:31

What do you not understand?

#22 Re: Help Me ! » Mathematics » 2017-01-11 23:12:32

Hi;

I like them too...Is there some question you have about them?

#23 Re: Exercises » degrees » 2017-01-11 16:35:10

Hi;

Because of the substitution in post #2.

#24 Re: Help Me ! » Find all the n numbers » 2017-01-11 10:42:09

What makes you think there are more?

#25 Re: Help Me ! » Find all the n numbers » 2017-01-11 07:46:51

Hi;

n = 13 can be found quickly.

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