Home
Class 12
MATHS
If veca, vecb, vecc are three non coplan...

If `veca, vecb, vecc` are three non coplanar, non zero vectors then `(veca.veca)(vecbxxvecc)+(veca.vecb)(veccxxveca)+(veca.vecc)(vecaxxvecb)` is equal to

A

`[(veca, vecb, vecc)]vecc`

B

`[(vecb, vecc, veca)]veca`

C

`[(vecc, veca, vecb)]vecb`

D

none of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the expression: \[ (\vec{a} \cdot \vec{a})(\vec{b} \times \vec{c}) + (\vec{a} \cdot \vec{b})(\vec{c} \times \vec{a}) + (\vec{a} \cdot \vec{c})(\vec{a} \times \vec{b}) \] where \(\vec{a}, \vec{b}, \vec{c}\) are three non-coplanar, non-zero vectors. ### Step 1: Rewrite the expression using properties of dot and cross products We can use the properties of the dot product and the cross product. Recall that the scalar triple product \((\vec{a} \cdot (\vec{b} \times \vec{c}))\) can be represented as the volume of the parallelepiped formed by the vectors \(\vec{a}, \vec{b}, \vec{c}\). ### Step 2: Group the terms We can group the terms in the expression: \[ \vec{a} \cdot \vec{a} (\vec{b} \times \vec{c}) + \vec{a} \cdot \vec{b} (\vec{c} \times \vec{a}) + \vec{a} \cdot \vec{c} (\vec{a} \times \vec{b}) \] ### Step 3: Use the scalar triple product identity Recall the identity for the scalar triple product: \[ \vec{a} \cdot (\vec{b} \times \vec{c}) = \vec{b} \cdot (\vec{c} \times \vec{a}) = \vec{c} \cdot (\vec{a} \times \vec{b}) \] This means that we can express each of the terms in terms of the scalar triple product. ### Step 4: Substitute using the scalar triple product Using the scalar triple product, we can rewrite the expression: 1. The first term becomes \((\vec{a} \cdot \vec{a}) (\vec{b} \times \vec{c})\). 2. The second term becomes \((\vec{a} \cdot \vec{b}) (\vec{c} \times \vec{a})\). 3. The third term becomes \((\vec{a} \cdot \vec{c}) (\vec{a} \times \vec{b})\). ### Step 5: Recognize that two vectors are the same Notice that in the third term, \(\vec{a} \times \vec{a} = 0\). Thus, the third term vanishes. ### Step 6: Combine the remaining terms Now we have: \[ (\vec{a} \cdot \vec{a})(\vec{b} \times \vec{c}) + (\vec{a} \cdot \vec{b})(\vec{c} \times \vec{a}) = (\vec{a} \cdot \vec{b})(\vec{c} \times \vec{a}) + 0 \] ### Step 7: Use the cyclic property of scalar triple product By the cyclic property of the scalar triple product, we can express the remaining terms as: \[ \vec{a} \cdot (\vec{b} \times \vec{c}) + \vec{b} \cdot (\vec{c} \times \vec{a}) + \vec{c} \cdot (\vec{a} \times \vec{b}) = 0 \] ### Conclusion Thus, the final value of the expression is: \[ \vec{a} \cdot (\vec{b} \times \vec{c}) = V \] where \(V\) is the volume of the parallelepiped formed by \(\vec{a}, \vec{b}, \vec{c}\).

To solve the problem, we need to evaluate the expression: \[ (\vec{a} \cdot \vec{a})(\vec{b} \times \vec{c}) + (\vec{a} \cdot \vec{b})(\vec{c} \times \vec{a}) + (\vec{a} \cdot \vec{c})(\vec{a} \times \vec{b}) \] where \(\vec{a}, \vec{b}, \vec{c}\) are three non-coplanar, non-zero vectors. ...
Promotional Banner

Topper's Solved these Questions

  • SCALAR AND VECTOR PRODUCTS OF THREE VECTORS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Section II - Assertion Reason Type|12 Videos
  • SCALAR AND VECTOR PRODUCTS OF THREE VECTORS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Exercise|63 Videos
  • SCALAR AND VECTOR PRODUCTS OF THREE VECTORS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Exercise|63 Videos
  • REAL FUNCTIONS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Chapter Test|58 Videos
  • SCALER AND VECTOR PRODUCTS OF TWO VECTORS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Section I - Solved Mcqs|12 Videos

Similar Questions

Explore conceptually related problems

If veca, vecb, vecc are non-coplanar non-zero vectors, then (vecaxxvecb)xx(vecaxxvecc)+(vecbxxvecc)xx(vecbxxveca)+(veccxxveca)xx(veccxxvecb) is equal to

If veca, vecb and vecc are three non-coplanar non-zero vectors, then prove that (veca.veca) vecb xx vecc + (veca.vecb) vecc xx veca + (veca.vecc)veca xx vecb = [vecb vecc veca] veca

If veca, vecb, vecc are any three non coplanar vectors, then (veca+vecb+vecc).(vecb+vecc)xx(vecc+veca)

If vec a , vec ba n d vec c are three non-zero non-coplanar vectors, then the value of (veca.veca)vecb×vecc+(veca.vecb)vecc×veca+(veca.vecc)veca×vecb.

If veca, vecb and vecc are three non-coplanar vectors, then (veca + vecb + vecc). [(veca + vecb) xx (veca + vecc)] equals

If veca, vecb, vecc are any three non coplanar vectors, then [(veca+vecb+vecc, veca-vecc, veca-vecb)] is equal to

If veca, vecb and vecc are three non-coplanar vectors, then find the value of (veca.(vecbxxvecc))/(vecb.(veccxxveca))+(vecb.(veccxxveca))/(vecc.(vecaxxvecb))+(vecc.(vecbxxveca))/(veca.(vecbxxvecc))

If veca, vecb, vecc are non-coplanar vectors, then (veca.(vecb xx vecc))/(vecb.(vecc xx veca)) + (vecb.(vecc xx veca))/(vecc.(veca xx vecb)) +(vecc.(vecb xx veca))/(veca. (vecb xx vecc)) is equal to:

If vecA, vecB, vecC are non-coplanar vectors then (vecA.vecBxxvecC)/(vecCxxvecA.vecB)+(vecB.vecAxxvecC)/(vecC.vecAxxvecB)=

If veca, vecb, vecc are non-null non coplanar vectors, then [(veca-2vecb+vecc, vecb-2vecc+veca, vecc-2veca+vecb)]=

OBJECTIVE RD SHARMA ENGLISH-SCALAR AND VECTOR PRODUCTS OF THREE VECTORS -Section I - Solved Mcqs
  1. Let veca=2hati+3hatj-hatk and vecb=hati-2hatj+3hatk. Then , the value ...

    Text Solution

    |

  2. Let veca, vecb, vecc be three unit vectors such that veca. vecb=veca.v...

    Text Solution

    |

  3. If veca, vecb, vecc are three non coplanar, non zero vectors then (vec...

    Text Solution

    |

  4. If the acute angle that the vector alphahati+betahatj+gammahatk makes ...

    Text Solution

    |

  5. If veca,vecb,vecc are three non-coplanar vectors and vecp,vecq,vecr ar...

    Text Solution

    |

  6. If veca vecb are non zero and non collinear vectors, then [(veca, vecb...

    Text Solution

    |

  7. If vecr is a unit vector such that vecr=x(vecbxxvecc)+y(veccxxveca)+...

    Text Solution

    |

  8. Let a,b,c be three vectors such that [a b c]=2, if r=l(bxxc)+m(cxxa)+n...

    Text Solution

    |

  9. If vecb is a unit vector, then (veca. vecb)vecb+vecbxx(vecaxxvecb) is ...

    Text Solution

    |

  10. If veca, vecb, vecc are any three non coplanar vectors, then [(veca+ve...

    Text Solution

    |

  11. If veca, vecb, vecc are any three non coplanar vectors, then (veca+v...

    Text Solution

    |

  12. Let veca, vecb and vecc be three having magnitude 1,1 and 2 respective...

    Text Solution

    |

  13. If veca = (hati + hatj +hatk), veca. vecb= 1 and vecaxxvecb = hatj -ha...

    Text Solution

    |

  14. If veca, vecb, vecc are non-coplanar non-zero vectors, then (vecaxxv...

    Text Solution

    |

  15. If the vectors veca, vecb, vecc and vecd are coplanar vectors, then (...

    Text Solution

    |

  16. (vecaxxvecb).(veccxxvecd) is not equal to

    Text Solution

    |

  17. Let veca = 2hati + hatj + hatk, and vecb = hati+ hatj if c is a vecto...

    Text Solution

    |

  18. If veca,vecb and vecc are three non coplanar vectors and vecr is any v...

    Text Solution

    |

  19. The number of faces of a triangular pyramid or tetrahedron is .

    Text Solution

    |

  20. The acute angle that the vector 2hati-2hatj+hatk makes with the plane ...

    Text Solution

    |