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Prove that: t a n 70^0=t a n 20^0+2t a n...

Prove that: `t a n 70^0=t a n 20^0+2t a n 50^0dot`

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ALLEN-TRIGONOMETRIC RATIOS AND IDENTITIES-All Questions
  1. If sintheta=-1/2a n d\ t a ntheta=1/(sqrt(3))t h e n\ theta s equal t...

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  2. Show that sqrt(3)\ cos e c\ 20^0-sec20^0=4.

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  3. Prove that: t a n 70^0=t a n 20^0+2t a n 50^0dot

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  4. If sin2A= lambda sin 2B prove that (tan(A+B)/tan(A-B))=(lambda+1)/(la...

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  5. (sin5theta+sin2theta-sintheta)/(cos5theta+2cos3theta+2cos^2theta+costh...

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  6. Prove that: sin 12^0sin 48^0sin 54^0=1/8dot

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  7. Prove that (2cos2A+1)/(2cos2A-1)=tan(60^0+A)tan(60^0-A)dot

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  8. Prove that :t a n A+tan(60^0+A)+tan(120^0+A)=3t a n3A

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  9. sin (67(1)/2)^(@)+cos(67(1)/2)^(@) is equal to

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

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

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

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

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

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

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

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

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

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

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