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If A,B,C,D are the angles of a quadrila...

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

A

0

B

1

C

-1

D

2

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AAKASH SERIES-TRIGONOMERTIC RATIOS-EXERCISE - I
  1. sum(k=1)^3 cos^(2)((2k-1)(pi)/(12))=

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  2. tan1^(@).tan2^(@).tan3^(@)...tan89^(@)=

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  3. log10 tan1^@+log10 tan2^@+log10 tan3^@+......+log10 tan89^@=..........

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  4. cot. (pi)/(20) cot. (3pi)/(20) cot. (5pi)/(20) cot. (7pi)/(20) cot. (9...

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  5. Sin24^(@)+sin32^(@)+sin204^(@)+sin212^(@)=

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  6. cos. (pi)/(7) + cos. (2pi)/(7) + cos. (3pi)/(7) + cos. (4pi)/(7) + cos...

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

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

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  9. If sum(i=1)^(n)sin theta(i)=n then cos theta(1) + cos theta(2) + ...+c...

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  10. If sin theta + cosec theta =2 then sin^(n) theta + cosec^(n) theta =

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  11. (1+sec theta - tan theta)/(1+sec theta + tan theta)=

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  12. If sec theta + tan theta = 1.5 then theta lies in the quadrant

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  13. If x=sin 130^(@) + cos 130^(@) then

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  14. If u(n) = cos^(n) theta + sin^(n) theta then 2u(6)-3u(4)=

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  15. 3[sin^(4)(3pi//2-alpha)+sin^(4)(3pi+alpha)]-2[sin^(6)(pi//2+alpha)+sin...

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  16. If k=(1+ sin A) (1+ sin B)(1+ sin C)=(1- sin A) (1- sin B) (1- sin C) ...

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  17. If x=a cos^(3) theta , y= a sin^(3) theta then

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  18. If x= a sec^(n) theta , y = b tan^(n) theta then (x/a)^(2//n) -(y/b)^(...

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  19. If a=x sec theta + y tan theta , b = x tan theta + y sec theta then x...

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  20. If sin theta + cos theta =p and tan theta+ cot theta = q then q (p^(2...

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