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If A ,\ B ,\ C ,\ D are angles of a cycl...

If `A ,\ B ,\ C ,\ D` are angles of a cyclic quadrilateral, prove that `cos A+cos B+cos C+cos D=0.`

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RD SHARMA ENGLISH-TRIGONOMETRIC FUNCTIONS-All Questions
  1. Prove that: cos510^0cos 330^0+sin 390^0cos 120^0=-1.

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  2. Prove that ("cos"(90^0+theta)"sec"(-theta)"tan"(180^0-theta))/("sec"(3...

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  3. If A ,\ B ,\ C ,\ D are angles of a cyclic quadrilateral, prove that c...

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  4. Find the values of the following trigonometric ratio: sin ((5pi)/3) .

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  5. Find the values of the following trigonometric ratio: sin 3060^@

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  6. Find the values of the following trigonometric ratio: tan ((11pi)/6)

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  7. Find the values of the following trigonometric ratio: cos (1125^@)

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  8. Find the values of the following trigonometric ratio: tan315^0

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  9. Find the values of the following trigonometric ratio: cosec\ (-1200^0)

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  10. Find the values of the following trigonometric ratio: cos1755^0

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  11. Find the values of the following trigonometric ratio: sin510^0

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  12. Find the values of the following trigonometric ratio: tan(-585^0)

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  13. Find the values of the following trigonometric ratio: sin 4530^0

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  14. Find the values of the following trigonometric ratio: cos570^0

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  15. Find the values of the following trigonometric ratio: cos 855^0

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  16. Find the values of the following trigonometric ratio: "sin"(-330^0)

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  17. Find the values of the following trigonometric ratio: sin1845^0

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  18. Prove that: t a n 225^0cot 405^0+t a n 765^0cot 675^0=\ 0

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  19. Prove that: sin ((8pi)/3) cos ((23pi)/6)+cos ((13pi)/3) sin ((35pi)/6)...

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  20. Prove that: cos 24^0+cos55^0+cos 125^0+cos 204^@+cos 300^0=1/2

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