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## #1 2014-05-04 03:40:37

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
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### Trig - Compound Angles

Prove that

tan 8θ - tan 6θ - tan 2θ = (tan 8θ)(tan 6θ)(tan 2θ)

'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'
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## #2 2014-05-04 03:57:28

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
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### Re: Trig - Compound Angles

Proof

Last edited by Agnishom (2014-05-04 22:20:19)

'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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## #3 2014-05-04 08:19:56

bob bundy
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Registered: 2010-06-20
Posts: 7,067

### Re: Trig - Compound Angles

hi Agnishom,

Nice solution!    But check line 5 out of 6.

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

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## #4 2014-05-04 13:25:23

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

### Re: Trig - Compound Angles

Agnishom wrote:

Prove that

tan 8θ - tan 6θ - tan 2θ = (tan 8θ)(tan 6θ)(tan 2θ)

I haven't looked at your proof, but here's what I would do:

tan8θ - tan6θ - tan2θ
= tan8θ-(tan6θ + tan2θ)
= tan8θ - tan(6θ + 2θ)(1 - tan6θ * tan2θ)
= tan8θ - tan8θ * (1 - tan6θ * tan2θ)
= tan8θ(1 - 1 + tan6θ * tan2θ)
= tan8θ * tan6θ * tan2θ

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## #5 2014-05-04 22:20:55

Agnishom
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From: Riemann Sphere
Registered: 2011-01-29
Posts: 21,756
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### Re: Trig - Compound Angles

Fixed it, Bob

Shivam, That is the same thing I've done. Thanks for helping, though.

'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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## #6 2014-05-05 01:02:14

bob bundy
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Registered: 2010-06-20
Posts: 7,067

### Re: Trig - Compound Angles

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

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