Trigonometry- Basic Identities help?

Purple Gorilla · 2009-02-26 21:54:50

Hola :) I'm doing Basic Identities for homework and I need some help with a question :) The question is: cot2θ (1-cos2θ) = cos2θ The numbers in bold are actually indices (Cot-squared) I'd really appreciate if someone could explain how to do it? Thanks :)

26-02-2009 10:54PM

#1

Purple Gorilla

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Hola

I'm doing Basic Identities for homework and I need some help with a question

The question is:

cot2θ (1-cos2θ) = cos2θ

The numbers in bold are actually indices (Cot-squared)

I'd really appreciate if someone could explain how to do it?

Thanks

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#2 27-02-2009 12:02AM

seandoiler

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Join Date: March 2006

Posts: 104

Purple Gorilla wrote: »

Hola
The question is:

cot2θ (1-cos2θ) = cos2θ

cot(theta)=1/tan(theta)=cos(theta)/sin(theta)....
cot^2(theta)=cos^2(theta)/sin^2(theta)
1-cos^2(theta)=sin^2(theta)...

so cot^2(theta)(1-cos^2(theta))=cos^2(theta)

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