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Using vector method prove that cos(A-B)=...

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

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MODERN PUBLICATION-VECTORS-Exercise
  1. In any triangle ABC, then by vectors, prove that : a=b cos C+c cos B.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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  17. The value of : hati*(hatjxxhatk)+hatj*(hatixxhatk)+hatk*(hatixxhatj) i...

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  18. Find the value of 'p' is : (2hati+6hatj+27hatk)xx(hati+3hatj+phatk)=ve...

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  19. If veca=hati-hatj+2hatk and vecb=2hati+hatj-hatk, find : (2veca-vecb)x...

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  20. Find vecaxxvecb, if veca=2hati+hatj+3hatk and vecb=3hati+5hatj-2hatk

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