Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

I see

bobbym wrote:

This way is easier to understand at first but I wanted to show you how it was done with mods first. For these MO problems a very good understanding of the properties of mods is required.

Any article or anything you would suggest me to read for clearing my idea on mods?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

Hi Agnishom;

When you get some time go here.

http://betterexplained.com/articles/fun … rithmetic/

http://betterexplained.com/articles/fun … rithmetic/

http://www.math.okstate.edu/~wrightd/cr … ode12.html

Have patience and do not expect to understand it all at once.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

Would you suggest any good book that is freely available for Number Theory?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

Hi Agnishom;

I will need to think about it. I will post one here.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

**noelevans****Member**- Registered: 2012-07-20
- Posts: 236

Hi phrontister!

I had never noticed those symbols! Thanks for pointing them out.

Writing "pretty" math (two dimensional) is easier to read and grasp than LaTex (one dimensional).

LaTex is like painting on many strips of paper and then stacking them to see what picture they make.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

Hi Agnishom;

Look for this book it was my first number theory book.

"Recreations in the Theory of Numbers" by

Albert H. Beiler

It will be tough in some spots so do not be afraid to jump around. Since you have programming skills you might want to solve some of the problems in that way.

It stresses a problem solving approach. It is not exactly an introductory text but I do not believe there is one and I have looked at hundreds.

Number theory is the mathematicians favorite and they are not willing to give up its secrets without a fight.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

Thanks! I will try to find it

Question 8: ** Find all integer sided triangles whose area and peremeter are equal**

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**noelevans****Member**- Registered: 2012-07-20
- Posts: 236

Answer:

Writing "pretty" math (two dimensional) is easier to read and grasp than LaTex (one dimensional).

LaTex is like painting on many strips of paper and then stacking them to see what picture they make.

Offline

Excuse me noelevans, I think we had been talking about **Triangles**

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**scientia****Member**- Registered: 2009-11-13
- Posts: 224

Let the sides be . The perimeter is and the area is by Heron's formula.

Hence

Setting

:Since

are sides of a triangle, we can make the substitution , , , which givesThus

are integers, as are integers; they are also positive as the sum of two sides of a triangle must be strictly greater than the third side. Substituting in the above equation:So the RHS is divisible by 4. This means either (i) two of

equal 2, or (ii) one of equals 4. In case (i) we have (taking WLOG) , an absurdity. So case (ii) must hold. WLOG let . ThenThus

must be an integer or , which gives or .Substituting back gives

or . Hence the only triangle with equal area and perimeter is the one with sides 6, 8, 10.*Last edited by scientia (2012-12-09 22:58:27)*

Offline

**scientia****Member**- Registered: 2009-11-13
- Posts: 224

Sorry, I made a mistake.

This means that either are integers or of the form for . There may be other answers.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

Hi scientia;

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

**scientia****Member**- Registered: 2009-11-13
- Posts: 224

Yeah, as I said I made a mistake.

Let , , , where are positive integers (so themselves are not necessarily integers). This gives

which is what is required to be solved.

I haven't gone very far, have I?

*Last edited by scientia (2012-12-10 00:25:49)*

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

Hi scientia;

I wasn't correcting I was just hoping that you could make a simple adjustment to your way if you saw more data. I do not even know yet if those are the only possible solutions.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

What are these x,y and z?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**noelevans****Member**- Registered: 2012-07-20
- Posts: 236

Hi Agnishom!

Boy! Did I misread the problem or what? Sure was easy for the square, but a horse of a different

color for the triangles. I think you will find that the only two Pythagorean triples that will work are

the first two that bobbym listed. The basic Pythagorean triples are of the form

(u²+v², u²-v², 2uv) with 0<v<u.

(6,8,10) is a scalar multiple of (3,4,5); that is, (2*3,2*4,2*5) where u=2 and v=1.

(5,12,13) is a basic Pythagorean triple where u=3 and v=2.

I would have responded sooner, but my internet connection has been out.

Have a great day!

Writing "pretty" math (two dimensional) is easier to read and grasp than LaTex (one dimensional).

LaTex is like painting on many strips of paper and then stacking them to see what picture they make.

Offline

Excuse me noelevans, What if the triangle isn't right angled?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

Hi Agnishom;

There are 5 solutions, I just can not post the proof to that.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

Then How did you work them out?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

The proof supplied the 5 answers. I checked them using geogebra and that was not easy either.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

Do you have the proof?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

Hi;

Yes I do but it is not mine and the last part I do not understand well enough.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

I just can not post the proof to that.

Why? Whats wrong?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 98,920

For one thing, it could be wrong! If I do not understand it how can I explain it or be satisfied with it? Oh, he/she is right with the five solutions he gives. I checked them and they are correct. But supposing there are a couple of more solutions?

I will post it if you would like to see it.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **Thinking is cheating.**

Offline

Please show me

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

Offline