Math Is Fun Forum

Trig Student

Guest

Trig Identity - Urgent Help Needed

Hey guys,

I'm really stuck on this question. I have been working at it for hours.

I need to prove this identity:

Please help.

Thank you very much in advance!!

Greatly appreciated.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Trig Identity - Urgent Help Needed

Hi Trig;

Follows easily from these 2 identities:

Last edited by bobbym (2009-11-02 09:48:48)

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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.

Trig Student

Guest

Re: Trig Identity - Urgent Help Needed

We have only learnt the standard trig identities and the double angle formulae.

Is there a way of doing it using those identities?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Trig Identity - Urgent Help Needed

Hi Trig;

Do you know Cos²(x) and Sin²(x) ?

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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.

Trig Student

Guest

Re: Trig Identity - Urgent Help Needed

Hello Bobbym,

I don't know those identities either. =S

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Trig Identity - Urgent Help Needed

Hi Trig;

Then you know this one:

or

Can you use these?

Last edited by bobbym (2009-11-02 11:15:21)

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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.