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The value of sin 78^0-sin 66^0-sin 42^0+...

The value of `sin 78^0-sin 66^0-sin 42^0+sin6^0` is `-1` b. `1//2` c. `-1//2` d. none of these

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ALLEN-TRIGONOMETRIC RATIOS AND IDENTITIES-All Questions
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  2. sin (67(1)/2)^(@)+cos(67(1)/2)^(@) is equal to

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  3. The value of sin 78^0-sin 66^0-sin 42^0+sin6^0 is -1 b. 1//2 c. -1//2 ...

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  4. In any triangle A B C ,\ sin A-cos B=cos C ,\ the angle\ B is a.pi...

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  5. If A+B+C=(3pi)/2 , then cos2A+cos2B+cos2C is equal to a.1-4cos Acos...

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  6. Prove that 5costheta+3cos(theta+pi/3)+3 lies between -4 and 10.

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  7. The maximum value of 1+sin(pi/4+theta)+2cos(pi/4-theta) for real value...

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  8. Prove that t a n A+2t a n2A+4t a n4A+8cot8A=cot Adot

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  9. sum(r=1)^(n-1)cos^2((rpi)/n)

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  10. Prove that: (1+sec2theta)(1+sec4theta)(1+sec8theta)(1+sec2^ntheta)=t a...

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  11. To find sum of tangents of a series of angles, the angles being in Ari...

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  12. S=cosecx+cosec 2x+cosec 4x+…+cosec 2nx=cot(x/2)−cot2nx

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  13. The expression (tan(x-pi/2)cos((3pi)/2+x)-sin^3((7pi)/2-x))/(cos(x-pi/...

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  14. The values of cos^2 73^0+cos^2 47^0-sin^2 43^0+sin^2 107^0 is equal t...

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  15. The expression (sin 22^0cos8^0+cos 158^0cos98^0)/(sin 23^0cos7^0+cos 1...

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  16. The two legs of a right triangle are sin theta +sin ((3pi)/2-theta) an...

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  19. (The tangents of two acute angles are 3 and 2, The sine of twice their...

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  20. Exact value of cos 20^0+2sin^2\ \ 55^0-sqrt(2)sin65^0\ is- a.1 b. 1/(...

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