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In a DeltaABC, if (2cosA)/a+(cosB)/b+(2c...

In a `DeltaABC`, if `(2cosA)/a+(cosB)/b+(2cosC)/c=a/(bc)+b/(ca)`, prove that `angleA=90^(@)`.

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NAGEEN PRAKASHAN ENGLISH-TRIGNOMETRIC FUNCTIONS-EXERCISES 3N
  1. In DeltaABC, prove that: b(cosA-cosC)=2(c-a)cos^(2)B/2

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  2. i) In DeltaABC, prove that: (b-a)/(b+a)=tanC/2. tan(B-A)/(2) ii) In ...

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  3. In DeltaABC, prove that: a/(b+c)=(1-tanB/2tanC/2)/(1+tanB/2tanC/2)

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  4. In DeltaABC, prove that: a^(2)sin2B+b^(2)sin2A=2 ab sinC

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  5. Prove that, (asin(B-C))/(b^(2)-c^(2)) = (bsin(C-A))/(c^(2)-a^(2)) = ...

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  6. In any DeltaABC, prove that ac""cosB-bc""cosA=a^(2)-b^(2)

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  7. In any triangle A B C , prove that following: \ (a^2"sin"(B-C))/(sin A...

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  8. In DeltaABC, prove that: (1+cosA.cos(B-C))/(1+cosC.cos(A-B))=(b^(2)+c...

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  9. In DeltaABC, (b^(2)+c^(2))sin(B-C)=(b^(2)-c^(2))sin(B+C), then prove t...

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  10. In a A B C , if cosC=(sinA)/(2sinB) , prove that the triangle is isos...

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  11. In triangleABC, cosA=sinB-cosC,prove that DeltaABC, is right angled.

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  12. If (sinA)/(sinC)=(sin(A-B))/(sin(B-C)), prove that a^(2), b^(2), c^(2)...

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  13. In a triangle ABC, prove that for any angle theta, b cos (A - theta) +...

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  14. In DeltaABC, 1/a,1/b,1/c are in A.P. prove that "cosec"^(2)A/2, "cosec...

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  15. If a=5, b=12 and c=13, find tanA.

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  16. The sides of a triangle are x^(2) + x + 1, 2 x + 1, and x^(2) -1. Prov...

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  17. i) In DeltaABC, if b=17, c=11 and angleA=60^(@), find tan(B-C)/(2)

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  18. In any DeltaABC , prove that (a-b)^(2)cos^(2)(C/2)+(a+b)^(2)sin^(2)(C ...

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  19. In DeltaABC, prove that: (b^(2)-c^(2)+a^(2))tanC=(b^(2)+c^(2)-a^(2))...

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  20. In a DeltaABC, if (2cosA)/a+(cosB)/b+(2cosC)/c=a/(bc)+b/(ca), prove th...

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