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Prove that, in any triangle ABC, cos B=(...

Prove that, in any triangle ABC, `cos B=(c^2+a^2-b^2)/(2ca)`.

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MODERN PUBLICATION-VECTORS-Exercise
  1. In any DeltaABC prove by vectors that b^2=c^2+a^2-2 ca cos B.

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  2. In any triangle ABC, then by vectors, prove that : c^2=a^2+b^2-2ab cos...

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  3. Prove that, in any triangle ABC, cos B=(c^2+a^2-b^2)/(2ca).

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  4. With the help of vector method, prove that,cosA=(b^2+c^2-a^2)/(2bc)

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  5. In any triangle ABC, then by vectors, prove that : a=b cos C+c cos B.

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  6. Use vectors to prove that in triangleABC : b=c cos A+a cos C.

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  7. Using vector method prove that cos(A-B)=cosAcosB+sinAsinB

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  8. In any triangle ABC, show that AB^(2)+AC^(2)=2(AD^(2)+BD^(2)) wher...

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  9. Prove that any two edges in a regular tetrahedron are perpendicular.

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  10. In each problem, find the work done by a force vecF acting on a partic...

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  11. In each problem, find the work done by a force vecF acting on a partic...

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  12. Find the work done by the force vecF=hati+2hatj+hatk acting on a parti...

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  13. Find the work done in moving an object along the vector vecd=3hati+2ha...

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  14. A particle acted by constant forces 4 hat i+ hat j-3 hat k and 3 hat...

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  15. Constant forces 2hati-5hatj+6hatk and hati+2hatj-hatk act on a particl...

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  16. Forces of magnitudes 5 and 3 units acting in the directions 6hati + ...

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  17. Which is greater: 45 kg or 4500 g?

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  18. Find vecaxxvecb, if : veca=-hati+3hatk and vecb=hati+3hatj-2hatk.

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  19. Find vecaxxvecb, if : veca=hati-3hatj+4hatk and vecb=2hati+hatj+hatk.

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  20. The value of : hati*(hatjxxhatk)+hatj*(hatkxxhati)+hatk*(hatjxxhati) i...

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