# Math Is Fun Forum

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

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## #26 2010-09-06 01:35:43

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

if A is area of triangle &a,b,c are sides & R is radius of circumcircle which circumscribed the triangle

then prove that (a+b+c)>=3(4RA)^1/3

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## #27 2010-09-06 01:45:20

Bob
Registered: 2010-06-20
Posts: 10,516

### Re: provement

hi sameer,

Too many questions at once.  Just started to look at the range question.

But the sine ones are easier so I'll start there.

When you first meet sine and cosine it's in a right angled triangle.  diagram below

sine A = O/H

so when A = zero Opposite = zero, so sinA = zero

If you start with an equilateral triangle (all sides = 2) and cut it down the middle one half is a right angled triangle.

The angles are 30, 60 90 and H= 2, 'O' = 1 so sin 30 = 1/2.

The range question suggests to me that you are now onto the more general definition of sine cosine and tangent which allows any angle not just those in a right angled triangle.  (see second diagram)

More will follow .... just want to check what I've done so far.  Please reply so I know you're ok so far.

Bob

Last edited by Bob (2010-09-06 01:46:34)

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #28 2010-09-06 01:57:14

Bob
Registered: 2010-06-20
Posts: 10,516

### Re: provement

Aaaarrrhhhh.  Yet another question.  Please slow down and take it one at a time.  I need to know you that understand the two sine questions.  There's no point me going on to the range and circumcircle questions until I get your answer to that.

Latest question:  Do you mean ?

Also, looking back, I cannot find any response from you to posts 13, 14 , 17 and 18.  When you ask for help and someone posts you a question in order to help, you need to respond or we'll lose interest.

bob

Last edited by Bob (2010-09-06 02:01:36)

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #29 2010-09-06 02:45:38

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Hi bob bundy;

I don't think you are going to get a response. At least I haven't been able to get one.

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.

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## #30 2010-09-06 06:38:47

Bob
Registered: 2010-06-20
Posts: 10,516

### Re: provement

Hi bobbym,

Thank you for posting on this.  At least I can feel as though someone is 'out there'.  This is an excellent example of what we were saying earlier.

He posted new questions faster than I could respond.

What puzzles me is the spread of levels of difficulty.  From basic sine work through to a fairly complex circumcircle question which took me a page of working, using two advanced trig formulas followed by a binomial expansion.  I'm not claiming that's the only way to do the problem but, however you do it, it's several orders of magnitude harder than "why is sin 0 =0 ?"

I'd could help if I could get a 'feel' for what the course is and what level the questioner is at with the work.  But, without a response I cannot do more.  If you're reading this sameer, TALK TO US!.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #31 2010-09-06 06:43:14

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Hi bob bundy;

Could be he is just posting questions randomly to get to his 10 post mark. He is at nine so let's see. To me the most interesting question he had was the optimization problem. 2 solutions were offered to him and he never even came back to 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.

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## #32 2010-09-07 01:07:48

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

if a,b,c are sides of a triangle & A be the area of triangle R will be radius of
circumcircle of that triangle
p.t (a+b+c)>=3{4RA}^1/3

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## #33 2010-09-07 01:12:40

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Hi sameer mishra;

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.

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## #34 2010-09-07 01:23:16

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

if you want solution of sin30=1/2 then search on google
"why sin30=1/2" am allready given solution on that

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## #35 2010-09-07 01:30:47

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

my friends i want to help
all of you know that
A=abc/4R
hence 4RA=abc
A.M>=G.M
(a+b+c )/3>=(abc)^1/3
now put the valu of abc=4RA
hence you can get the answer

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## #36 2010-09-07 01:34:28

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Hi sameer;

I am glad that you want to help. Please post these in "This is cool."

When you post them in Help me, you make people think you need help on something you already know the answer to.

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.

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## #37 2010-09-07 01:39:40

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

2 or 3 days before i ask a problem what is eaist way to find area of triangle i given sides as 1-(x)^1/2 ,5-(x)^1/2 ,7-(x)^1/2 friend all of you not thing about question
here triangle will not be form
triangle will form if (sum of smallest side )>=biggest side

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## #38 2010-09-07 01:41:15

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Not exactly I gave an answer to that question. It was hard work. I asked you some questions and got no answer.

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.

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## #39 2010-09-07 01:44:08

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

friend i ask one question related to range yesterday very intresting
try to solve it

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## #40 2010-09-07 02:01:10

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Hi;

In all fairness questions by bob bundy and I relating to posts 12,13,14,17,18 have been unanswered by you. Please answer the questions so that we may continue.

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.

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## #41 2010-09-07 08:15:27

Bob
Registered: 2010-06-20
Posts: 10,516

### Re: provement

hi bobbym

How are you today?  Thanks for once again trying.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #42 2010-09-07 08:21:54

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Hi bob bundy;

I am okay, how are you?

I had him here live, in person and he wasn't reading my responses. One thing is now known, there is no urgency to his questions. He is not seeking help, he is posing problems. I do not think I will to be able to get him to post where he is supposed to.

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.

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## #43 2010-09-07 21:49:45

Bob
Registered: 2010-06-20
Posts: 10,516

### Re: provement

Hi bobbym,

I'm well thanks.  I'm expecting to visit Niagara, then Yellowstone and Grand Canyon soon.  Big adventure for me.

I'm beginning to think he has difficulty with some of the more subtle nuances of English so he doesn't realise the difference between 'help me',  'puzzles and games' and 'exercises'.  Or the usefulness of starting a new thread with its own topic title.

Oh well, I guess we're all on a learning curve here.  Can you send him an email asking for his native language?  Then we could put out a request for someone who could translate for us.   Just a thought.

bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

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## #44 2010-09-14 01:37:13

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

what is range of 1/(3-5cosx)

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## #45 2010-09-14 01:37:43

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: provement

Hi bob;

Sorry, I didn't see this before you left. Sounds like a great trip. Have a good time.

I have been trying to PM him but with no success. Maybe he is not getting 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.

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## #46 2010-10-24 22:46:07

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

hiiii friends please try to ans a ques.
if X=0+i;
then what is valu of log(X)
where i represents a complex number

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## #47 2010-10-24 22:53:06

sameer mishra
Member
Registered: 2010-08-27
Posts: 64

### Re: provement

who will responsible for genration of trigonometry
please tell me about initial steps am not test you friend actually i want to know
because i want to work on this field

ALSO WRITE MATHMATICAL STEPS OF "GENRATION"

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