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

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

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

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

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

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

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

- Georg Cantor (1845-1918)

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

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

That looks like the ones.

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

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.

- Georg Cantor (1845-1918)

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

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

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

- Georg Cantor (1845-1918)

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

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

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.

Hope I'm right. :fingers crossed smiley

Bob

I'm hoping the odd powers cancel out.

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

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.

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

Agnishom wrote:

What is the fingers crossed smiley?

It is someone crossing their fingers.

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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.

Yes, I call her Watari because I call myself L

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

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

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

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I did it! Thank You!

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

Excellent!

Bob

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Please help me with proving

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

Hi Agnishom

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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