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In a triangle ABC, prove that for any an...

In a triangle ABC, prove that for any angle `theta, b cos (A - theta) + a cos (B + theta) = C cos theta`.

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NAGEEN PRAKASHAN-TRIGNOMETRIC FUNCTIONS-EXERCISES 3N
  1. In DeltaABC, if b=7, c=24, a=25, find angleA.

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  2. In DeltaABC, a:b:c=15:7:13, find cosA.

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  3. A triangle side are few 7 cm, 4sqrt3 cm and sqrt(13) cm then the smal...

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  4. In DeltaABC, a=x^(2)-1, b=2x+1, angleC=120^(@), find c.

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  5. In DeltaABC, prove that: a(cosB+cosC)=2(b+c)sin^(2)A/2.

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  6. In DeltaABC, prove that: b(cosA-cosC)=2(c-a)cos^(2)B/2

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

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  8. In DeltaABC, prove that: a^(2)sin2B+b^(2)sin2A=2absinC

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  9. If any triangle A B C , that: (asin(B-C))/(b^2-c^2)=(bsin(C-A))/(c^2-...

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  10. In DeltaABC, prove that: c(acosB-b cosA)=a^(2)-b^(2)

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  11. In DeltaABC, prove that: (a^(2)sin(B-C))/(sinA) + (b^(2)sin(C-A))/(s...

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  12. In DeltaABC, cosC=(sinA)/(2sinB), prove that b=c.

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

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  14. In DeltaABC, (sinA)(sinC) = (sin(A-B))/(sin(B-C)), prove that a^(2),b^...

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

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

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

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  18. The sides of a triangle are x^2+x+1, 2x+1 and x^2-1. Prove that the gr...

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

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

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