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#1 2014-05-05 05:32:10

Amrita
Member
From: Westing's House
Registered: 2014-04-30
Posts: 844

Trig Proof Help

    prove it.


In mathematics the art of proposing a question must be held of higher value than solving it.
                                                                                                                                                                  - Georg Cantor (1845-1918)

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#2 2014-05-05 06:36:33

bob bundy
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Registered: 2010-06-20
Posts: 7,018

Re: Trig Proof Help

hi Amrita,

Do you know the formulas for sinX + sinY and sinX - sinY ?

Use difference of two squares and these two formulas.

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#3 2014-05-05 06:56:36

Amrita
Member
From: Westing's House
Registered: 2014-04-30
Posts: 844

Re: Trig Proof Help

can u plz tell me the  formulae?


In mathematics the art of proposing a question must be held of higher value than solving it.
                                                                                                                                                                  - Georg Cantor (1845-1918)

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#4 2014-05-05 07:04:11

Amrita
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From: Westing's House
Registered: 2014-04-30
Posts: 844

Re: Trig Proof Help

hello bobym,how r u?talking 2 u after a long time.


In mathematics the art of proposing a question must be held of higher value than solving it.
                                                                                                                                                                  - Georg Cantor (1845-1918)

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#5 2014-05-05 07:10:14

bobbym
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From: Bumpkinland
Registered: 2009-04-12
Posts: 95,940

Re: Trig Proof Help

Hi;

Have not seen you in a few days.


In mathematics, you don't understand things. You just get used to them.

If it ain't broke, fix it until it is.

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#6 2014-05-05 07:14:49

Amrita
Member
From: Westing's House
Registered: 2014-04-30
Posts: 844

Re: Trig Proof Help

actually my 1 GB net in dongle was finished.can u plz tell me the formula bob bundy was talking about?


In mathematics the art of proposing a question must be held of higher value than solving it.
                                                                                                                                                                  - Georg Cantor (1845-1918)

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#7 2014-05-05 07:17:33

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 95,940

Re: Trig Proof Help

The only one I know offhand is:


In mathematics, you don't understand things. You just get used to them.

If it ain't broke, fix it until it is.

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#8 2014-05-05 07:21:36

bob bundy
Moderator
Registered: 2010-06-20
Posts: 7,018

Re: Trig Proof Help

That looks like the ones.  smile

Do you want me to show where they come from?  Starting with the compound angle formulas ....
Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#9 2014-05-05 07:24:51

Amrita
Member
From: Westing's House
Registered: 2014-04-30
Posts: 844

Re: Trig Proof Help

thnx. can u plz help with this sum?   if x+a is the hcf of x^2 + px +q and x^2 + lx + m,find the value of a.


In mathematics the art of proposing a question must be held of higher value than solving it.
                                                                                                                                                                  - Georg Cantor (1845-1918)

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#10 2014-05-05 07:26:20

bob bundy
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Registered: 2010-06-20
Posts: 7,018

Re: Trig Proof Help

I've done this recently for someone else, maybe Agnishom??

Just looking it up.................

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#11 2014-05-05 07:26:26

Amrita
Member
From: Westing's House
Registered: 2014-04-30
Posts: 844

Re: Trig Proof Help

yes bob,u can show them.i would like 2 know it.


In mathematics the art of proposing a question must be held of higher value than solving it.
                                                                                                                                                                  - Georg Cantor (1845-1918)

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#12 2014-05-05 07:27:52

bob bundy
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Registered: 2010-06-20
Posts: 7,018

Re: Trig Proof Help


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#13 2014-05-05 11:57:56

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,564
Website

Re: Trig Proof Help

bob bundy wrote:

I've done this recently for someone else, maybe Agnishom??

Just looking it up.................

Bob

Yes, you have. Because my Watari gave me this sum and I gave Amrita this sum


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#14 2014-05-20 20:05:33

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,564
Website

Re: Trig Proof Help

Please help me with proving this:


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#15 2014-05-20 20:48:15

bob bundy
Moderator
Registered: 2010-06-20
Posts: 7,018

Re: Trig Proof Help

hi Agnishom,

I haven't tried this yet (sound familiar ?) but this should work.

Start with (sin^2(x) + cos^2(x)) ^6 to get an expression for sin^6 + cos^6.

Use this to remove those terms from the expression.

Now do the same again with (sin^2(x) + cos^2(x)) ^4 to remove the fourth powers.

What's left will only have sin^2 and cos^2 terms so you should be able to twist it into the required result.  smile

Hope I'm right.  :fingers crossed smiley

Bob

I'm hoping the odd powers cancel out.


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#16 2014-05-20 21:04:50

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,564
Website

Re: Trig Proof Help

Start with (sin^2(x) + cos^2(x)) ^6 to get an expression for sin^6 + cos^6.

That is tedious.

What is the fingers crossed smiley?


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#17 2014-05-21 01:12:18

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,922

Re: Trig Proof Help

Agnishom wrote:
bob bundy wrote:

I've done this recently for someone else, maybe Agnishom??

Just looking it up.................

Bob

Yes, you have. Because my Watari gave me this sum and I gave Amrita this sum

Watari? Like from Death Note. smile


“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.

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#18 2014-05-21 01:15:27

ShivamS
Member
Registered: 2011-02-07
Posts: 3,646

Re: Trig Proof Help

Agnishom wrote:

What is the fingers crossed smiley?

It is someone crossing their fingers.

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#19 2014-05-21 01:52:27

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,564
Website

Re: Trig Proof Help

anonimnystefy wrote:
Agnishom wrote:
bob bundy wrote:

I've done this recently for someone else, maybe Agnishom??

Just looking it up.................

Bob

Yes, you have. Because my Watari gave me this sum and I gave Amrita this sum

Watari? Like from Death Note. smile

Yes, I call her Watari because I call myself L


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#20 2014-05-21 02:14:09

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,922

Re: Trig Proof Help

Really? That's cool. I'm not sure which character I have the most in common with.


“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.

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#21 2014-05-21 04:57:40

bob bundy
Moderator
Registered: 2010-06-20
Posts: 7,018

Re: Trig Proof Help

Agnishom wrote:

That is tedious.

Yes, but then again, you should have said "Have you got your glasses on Bob?  I think you meant:

and

Then start with the LHS of the required identity, multiply out the brackets, cancel some bits, factorise and use s^2 + c^2 = 1 lots of times and you'll get to

3 + 6 + 4 = 13 QED.

So get on with it!

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#22 2014-05-21 14:32:09

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,564
Website

Re: Trig Proof Help

I did it! Thank You!


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#23 2014-05-21 18:21:07

bob bundy
Moderator
Registered: 2010-06-20
Posts: 7,018

Re: Trig Proof Help

Excellent!

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#24 2014-06-03 01:33:56

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,564
Website

Re: Trig Proof Help

Please help me with proving


'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'
'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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#25 2014-06-03 02:55:55

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,922

Re: Trig Proof Help

Hi Agnishom

Solution


“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.

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