Math Is Fun Forum

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

A problem from 'The tangent'!!!

hi guys

here's a nice problem i've been struggling with:

Find all possible values for c if:

  a+b+c=4

and:

  a^2+b^2+c^2=8

and a,b,c are real numbers.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Hi;

Appears to be 2 rational solutions found so far:

You might be able to reduce the problem down to c depending on one parameter b.

Can you handle it now?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

i'm looking for irrational,and transcendental too.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Hi;

Do you see what is inside those square roots? You can figure all the solutions from that.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

yeah really easy -.-

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Hmmm. Does that mean yes or does that mean how?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

hi

i was ironic and sarcastic.

when you talk to me you must know that if it looks like a sarcasm it is likely that it is a sarcasm.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Well then a little background. Whether they be irrational or transcendental they can only occur when what is inside those square roots is positive. Otherwise c is imaginary, and you said you want c to be an element of the reals. Does that help?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

hi bobbym

i know that.i just can't do that kind of math right now.it's the last day of school here!

can we talk about topology?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

You do not know how to do an inequality? Then I will do it for you.

Since c depends on b, any b you pick in that range will determine c and a. So there are an infinite number of solutions. Also do not forget there are 2 equations for c.

I do probability, combinatorics, numerical analysis, calculus, linear algebra, computational math, geometry, number theory...

But never, never, never will you ever see me doing anymore topolgy or group theory.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

hi bobbym

i know how to do it,but i'm too bored to do it.

and why won't you talk about topology.what has it done to you?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Destroyed three of my productive years. Years I can not retrieve.

My friend you need to concentrate a bit harder and not abandon a problem so quickly.
Hard work and not talent or even genius is the key to success in everything you will ever attempt to do.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

hi bobbym

i will try to solve it but later.i won't give up on it.

and how has topology "destroyed three of my productive years"?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

My productive years, not yours.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

i know,but i am quoting if you didn't see.when you quote your referring to the subject as if you were the quotee.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

So what question are you asking?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

why has it destroyed 3 of your productive years?

Last edited by anonimnystefy (2011-12-30 00:45:40)

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Because I always want mathematics to solve problems. After 3 years of topology and group theory I still could not do anything but quote what Legendre and Gauss had already done. I did not like that. I got back into the fields I have mentioned and have been happy ever since.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

well i think that topology. plus it helped me understand the dilemma of a topologist who didn't know which one he should dip in, the doughnut or the coffee mug.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Yes, but that is the topologists problem. Heard of Tarski's paradox?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

yup.why?

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Fields that are full of paradoxes like that are apt to be incorrect and someday will be overhauled or dropped completely.

Why the sudden interest in topology?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

i don't know.i'm feeling like it.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: A problem from 'The tangent'!!!

Okay, what do you know about it?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: A problem from 'The tangent'!!!

well,not much.

i know a definition when two spaces are isomorphic:they are isomorphic when there is a continuous transformation fi from X to Y (which are topological spaces) that has a continuous inverse. i know why the line and the circle are not isomorphic (at least intuitively).and i can recognize when two spaces are isomorphic,also intuitively.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.