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(Projection Formulae) if `a ,b ,c` are the lengths of the sides opposite respectively to the angles `A ,B ,C` of a triangle `A B C ,` show that `a=bcosC+ccosB` (ii) `b=ccosA+acosC` (iii)`c=acosB+bcosA`

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RD SHARMA ENGLISH-SCALAR OR DOT PRODUCT-All Questions
  1. Express 2 hat i- hat j+3 hat k as the sum of vector parallel and a vec...

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  2. Show that the vectors vec a=3 hat i-2 hat j+ hat k , vec b= hat i+3 h...

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  3. (Projection Formulae) if a ,b ,c are the lengths of the sides opposite...

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  4. Prove using vectors: If two medians of a triangle are equal, then it i...

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  5. Find the angle between two vectors vec aa n d vec b with magnitudes s...

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  6. Find the angle between the vectors 5hat i+3 hat j+4 hat k and 6 hat i...

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  7. Find the projection of the vector 7 hat i+ hat j-4 hat kin vec a=2 hat...

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  8. For any vector vec r , prove that vec r=( vec r . hat i) hat i+( vec...

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  9. Find veca * vec b when vec a=2 hat i+2 hat j- hat ka n d vec b=6...

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  10. Find the value of lambda so that the vectors vec a=2 hat i+lambda hat...

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  11. Find the value of p for which the vectors vec a=3 hat i+2 hat j+9 ha...

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  12. Find the values of ' a ' which the vector vec r=(a^2-4) hat i+2 hat j...

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  13. If vec a , vec b , vec c are unit vector, prove that | vec a- vec b|...

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  14. If vec a , vec b , vec c are mutually perpendicular unit vectors, fin...

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  15. Find the value of c for which the vectors vec a=(clog2x) hat i-6 hat...

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  16. Let vec a= hat i+4 hat j+2 hat k ,\ \ vec b=3 hat i-\ 2 hat j+7 hat ...

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  17. Dot products of a vector with vectors 3 hat i-5 hat k ,2 hat i+7 hat j...

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  18. Let vec a , vec b , vec c be three vectors such that | vec a|=1,| vec...

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  19. (Cosine Formulae) if a ,b ,c are the lengths of the sides opposite res...

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  20. Prove that the altitudes of a triangle are concurrent.

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