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sum(k=1)^3 cos^(2)((2k-1)(pi)/(12))=...

`sum_(k=1)^3 cos^(2)((2k-1)(pi)/(12))=`

A

0

B

`1//2`

C

`-1//2`

D

`3//2 `

Text Solution

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The correct Answer is:
D
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DIPTI PUBLICATION ( AP EAMET)-TRIGONOMETRIC RATIOS AND IDENTITIES -EXERCISE 1 A ( TRIGONOMETRIC FUNCTIONS)
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  6. "cosec"(270^(@)-A)+"cosec"(90^(@)-A)+sec(90^(@)-A)+sec(270^(@)-A)=

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  8. In Delta ABC, cos""((3A+2B+C)/(2))+ cos""((A-C)/(2))=

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  10. In DeltaABC , tan""((A+B)/(2))*tan""(C)/(2)=

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  11. If A,B,C,D are the angles of a cyclic quadrilateral then sinA+sinB=

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  12. If A,B,C,D are the angles of a cyclic quadrilateral then cos A + cos...

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  13. If A,B,C,D are the angles of a quadrilateral then tan""((A+B)/(4))=

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  14. If A,B,C,D are the angles of a quadrilateral then cos""((A+B)/(2))+ ...

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  15. ( sin (-660^(@)) tan (1050^(@)) sec (-420^(@)))/(cos(225^(@)) "cosec"(...

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  16. (cos(180^(@)-A)*cot(90^@+A)*cos(-A))/(tan(180^(@)+A) tan(270^(@) +A)* ...

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  17. ( sin (15pi//9)*tan(4pi//3)*sec(-7pi//3))/(cot(-3pi//4)*cos(7pi//6)*"c...

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  18. (tan(35pi//6)*sin(-11pi//3)*sec(-7pi//3))/(cot(5pi//4)*"cosec"(7pi//4)...

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  19. sin""((pi)/2+ theta ) * cos (pi- theta ) * cot ""((3pi)/(2)+ theta ) -...

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  20. If tan 20^(@) = lambda , " then " (tan 250^@ + tan 340^(@))/(tan 200^...

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