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With the help of vector method, prove th...

With the help of vector method, prove that,`cosC=(a^2+b^2-c^2)/(2ab)`

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The correct Answer is:
`(a^(2)+b^(2)-c^(2))/(2ab)`
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ACCURATE PUBLICATION-VECTOR ALGEBRA-QUESTIONS CARRYING 2 MARKS
  1. If veca=2hati-2hatj+hatk , vecb=2hati-hatj+4hatk , and vecc=hati+2hatj...

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  2. Show that the vectors : 2hati-hatj+hatk,hati-3hatj-5hatk and 3hati-4ha...

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  3. With the help of vector method, prove that,cosC=(a^2+b^2-c^2)/(2ab)

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

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  6. Using vector method, prove that in a triangle, a=b cosC+ c cosB (proje...

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

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  8. Prove that in any triangle ABC,c=a cos B+b cosA

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  9. Using vector method, prove that the angle in a semi-circle is a right...

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  10. Show that the diagonals of a rhombus bisect each other at right angle...

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  11. If veca=hati-hatj+3hatk and vecb=2hati+3hatj-5hatk then find vecaxxvec...

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  12. If |veca|=5,|vecb|=8 and veca.vecb=24, then find |vecaxxvecb|

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  13. If |veca|=3,|vecb|=4 and veca.vecb=9 then find |vecaxxvecb|

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  14. Find a vector of magnitude 9, which is perpendicular to both the vecto...

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  15. Find a vector of magnitude 19, which is perpendicular to both the vect...

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  16. Find a vector of magnitude 7 , which is perpendicular to both the vect...

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  17. Determine the area of a parallelogram whose adjacent sides are represe...

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  18. Find the area of a parallelogram whose adjacent sides are : 3hati-4h...

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  19. Find the area of a parallelogram whose adjacent sides are veca=2hati-h...

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  20. Find the area of the parallelogram whose adjacent sides are given by t...

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