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Trigonomentry Question

If sin A , cos A , tan A are in Geometric Progression . then \(cot^{6} A - cot^{2} \)

the answer is 1

I wanted to know how? please Explain!

Note by Vamsi Krishna Appili
4 years, 3 months ago

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\(cos^{2}A=\frac{sin^{2}A}{cosA},\Rightarrow cot^{2}A=\frac{1}{cosA}.\)As in question \(cot^{6}A-cot^{2}A = \frac{1-cos^{2}A}{cos^{3}A} = \frac{sin^{2}A}{cos^{3}A} = 1.\)

Kishan K - 4 years, 3 months ago

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right

Anubhav Singh - 4 years, 3 months ago

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Comment deleted Jul 14, 2013

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Bt this is no harmonic progression man..

Krishna Jha - 4 years, 3 months ago

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but it is not in hp it is in gp frnd

Devashish Sharma - 4 years, 3 months ago

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dear vamsi ,plz match the question and then post

Shubham Gupta - 4 years, 3 months ago

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cos^2x=sin^2x!!!! Hence, cot^6x=cosec^2x!!! Therefore, by identity cosec^2x-cot^2x=1!!!!

Subhrodipto Basu Choudhury - 4 years, 3 months ago

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Calm down, that was understood without those exclamations also!

Akshat Jain - 4 years, 3 months ago

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what is this ^ ?

Devashish Sharma - 4 years, 3 months ago

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^ means a number raised to some power like 2^2 means \[\ 2^2\]

Cody Martin - 4 years, 3 months ago

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