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Using vector method, prove that in a tri...

Using vector method, prove that in a triangle, `a=b cosC+ c cosB` (projection formula)

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

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  2. If vec a+ vec b+ vec c= 0, show that the angletheta between vec a and ...

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

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  4. Show that the median to the base of ann isosceles triangle is perpendi...

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  5. Prove that in a right-angled triangle, the square of the hypotenuse is...

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

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  7. Prove that in a right angled triangle the mid-point of the hypotenuse ...

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  8. In a triangle OAB, angle AOB = 90^ @. If P and Q are the points of tri...

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  9. Which of the following statements are True or False : If the diagonals...

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  10. Prove that the quadrilateral obtained by joining mid-points of adjacen...

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  11. Prove that if the diagonals of a quadrilateral bisect each other at ri...

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  12. Using vector method, prove that the altitudes of a triangle are concur...

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  13. Prove that the perpendicular from the vertices to the opposite sides (...

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  14. Prove by vectors that : cos (alpha + beta) = cos alpha cos beta- sin...

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  15. Prove by vectors that : cos (alpha - beta) = cos alpha cos beta+ sin...

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  16. In each of the following , find the work done by a force vec F acting ...

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  17. In each of the following , find the work done by a force vec F acting ...

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  18. A particle acted on by two forces 4 hat i+ 3 hat j and 3 hat i+ 2 ha...

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  19. A particle is acted upon by constant forces 4hat(i)+hat(j)-3hat(k) an...

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  20. Find vec underset(1)(v)*vec underset(2)(v) if vec underset(1)(v)=3 hat...

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