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The value of cos((2pi)/7)cos((4pi)/7)cos...

The value of `cos((2pi)/7)cos((4pi)/7)cos((6pi)/7) `is

A

(-1/2)

B

(1/2)

C

(1/4)

D

(1/8)

Text Solution

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The correct Answer is:
D
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PATHFINDER-TRIGONOMETRIC RATIOS AND IDENTITIES-QUESTION BANK
  1. If tantheta=(sin alpha-cos alpha)/(sinalpha+cosalpha)1 then

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  2. The value of cos(pi/15)cos(2pi/15)cos(3pi/15)cos(4pi/15)cos(5pi/15)cos...

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  3. The value of cos((2pi)/7)cos((4pi)/7)cos((6pi)/7) is

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  4. The value of sin (pi/14)sin(3pi/14)sin(5pi/14)sin(7pi/14)sin(9pi/14)si...

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  5. If Pn=sin^ntheta+cos^ntheta where n in W (whole number)and theta in R ...

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  6. If Pn=sin^ntheta+cos^ntheta where n in W (whole number)and theta in R ...

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  7. If Pn=sin^ntheta+cos^ntheta where n in W (whole number)and theta in R ...

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  8. if f(theta)=acostheta+bsintheta then -sqrt(a^2+b^2)lef(theta)lesqrt(a^...

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  9. if f(theta)=acostheta+bsintheta then -sqrt(a^2+b^2)lef(theta)lesqrt(a^...

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  10. if f(theta)=acostheta+bsintheta then -sqrt(a^2+b^2)lef(theta)lesqrt(a^...

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  11. Find the range of A/2 if it satisfies 2 cos( A/2)=sqrt(1+sin A)-sqrt(1...

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  12. If for two sets A and B,A-B=A then which of the following is true?

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  13. Match List - I with List-II

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  14. Match List - I with List-II

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  15. Five cards are drawn successively with replacement from a well-shuffle...

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  16. If sin 47^@+sin61^@-sin11^@-sin25^@ equals cosk^@,then k=?

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  17. The value of e^(log10tan1^@+log10tan2^@+log10tan3^@+...+log10tan89^@ i...

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  18. cos((2pi)/7)+cos((4pi)/7)+cos((6pi)/7)

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  19. The values of a for which the equation sqrtasinx-2cosx=sqrt2+sqrt(2-a...

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  20. If un=cos^ntheta+sin^ntheta then 2u6-ku4+1=0 then the numerical quanti...

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