Home
Class 11
MATHS
If veca xx (vec b xx vecc) is perpendicu...

If `veca xx (vec b xx vecc)` is perpendicular to `(veca xx vecb ) xx vecc`, we may have

A

`(veca.vecc)|vecb|^(2)= (veca.vecb)(vecb.vecc)`

B

`veca.vecb=0`

C

`veca.vecc=0`

D

`vecb.vecc=0`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the given condition that \(\vec{a} \times (\vec{b} \times \vec{c})\) is perpendicular to \((\vec{a} \times \vec{b}) \times \vec{c}\). ### Step-by-Step Solution: 1. **Understanding the Cross Product**: The vector \(\vec{a} \times (\vec{b} \times \vec{c})\) can be rewritten using the vector triple product identity: \[ \vec{a} \times (\vec{b} \times \vec{c}) = (\vec{a} \cdot \vec{c}) \vec{b} - (\vec{a} \cdot \vec{b}) \vec{c} \] 2. **Rewriting the Second Vector**: Similarly, we can rewrite \((\vec{a} \times \vec{b}) \times \vec{c}\) using the same identity: \[ (\vec{a} \times \vec{b}) \times \vec{c} = (\vec{c} \cdot \vec{a}) \vec{b} - (\vec{c} \cdot \vec{b}) \vec{a} \] 3. **Setting Up the Perpendicular Condition**: Since \(\vec{a} \times (\vec{b} \times \vec{c})\) is perpendicular to \((\vec{a} \times \vec{b}) \times \vec{c}\), their dot product must be zero: \[ [(\vec{a} \cdot \vec{c}) \vec{b} - (\vec{a} \cdot \vec{b}) \vec{c}] \cdot [(\vec{c} \cdot \vec{a}) \vec{b} - (\vec{c} \cdot \vec{b}) \vec{a}] = 0 \] 4. **Expanding the Dot Product**: Expanding this dot product yields: \[ (\vec{a} \cdot \vec{c})(\vec{c} \cdot \vec{a}) \|\vec{b}\|^2 - (\vec{a} \cdot \vec{b})(\vec{c} \cdot \vec{b})(\vec{a} \cdot \vec{c}) - (\vec{a} \cdot \vec{c})(\vec{c} \cdot \vec{b})(\vec{a} \cdot \vec{b}) + (\vec{a} \cdot \vec{b})^2 (\vec{c} \cdot \vec{b}) = 0 \] 5. **Factoring the Expression**: We can factor out \((\vec{a} \cdot \vec{c})\): \[ (\vec{a} \cdot \vec{c}) \left[ \|\vec{b}\|^2 - (\vec{a} \cdot \vec{b})(\vec{c} \cdot \vec{b}) \right] = 0 \] 6. **Finding the Conditions**: From the factored expression, we have two cases: - Case 1: \(\vec{a} \cdot \vec{c} = 0\) (which means \(\vec{a}\) is perpendicular to \(\vec{c}\)) - Case 2: \(\|\vec{b}\|^2 = \vec{a} \cdot \vec{b} \cdot \vec{c} \cdot \vec{b}\) 7. **Conclusion**: Therefore, the conditions we derived indicate that either \(\vec{a} \cdot \vec{c} = 0\) or the second condition holds. We can check which options match these conditions.

To solve the problem, we need to analyze the given condition that \(\vec{a} \times (\vec{b} \times \vec{c})\) is perpendicular to \((\vec{a} \times \vec{b}) \times \vec{c}\). ### Step-by-Step Solution: 1. **Understanding the Cross Product**: The vector \(\vec{a} \times (\vec{b} \times \vec{c})\) can be rewritten using the vector triple product identity: \[ \vec{a} \times (\vec{b} \times \vec{c}) = (\vec{a} \cdot \vec{c}) \vec{b} - (\vec{a} \cdot \vec{b}) \vec{c} ...
Promotional Banner

Topper's Solved these Questions

  • DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS

    CENGAGE ENGLISH|Exercise Reasoning type|8 Videos
  • DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS

    CENGAGE ENGLISH|Exercise Comprehension type|27 Videos
  • DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS

    CENGAGE ENGLISH|Exercise Multiple correct answers type|11 Videos
  • CONIC SECTIONS

    CENGAGE ENGLISH|Exercise All Questions|1344 Videos
  • LIMITS AND DERIVATIVES

    CENGAGE ENGLISH|Exercise All Questions|691 Videos

Similar Questions

Explore conceptually related problems

If veca , vecb and vecc are non- coplanar vectors and veca xx vecc is perpendicular to veca xx (vecb xx vecc) , then the value of [ veca xx ( vecb xx vecc)] xx vecc is equal to

Let veca,vecb,vecc be three non coplanar and vecd be a vector which is perpendicular to veca + vecb + vecc . If vecd = xvecb xx vecc + yvecc xx veca + zveca xx vecb the-

Let veca vecb and vecc be non- zero vectors aned vecV_(1) =veca xx (vecb xx vecc) and vecV_(2) = (veca xx vecb) xx vecc .vectors vecV_(1) and vecV_(2) are equal . Then

Let veca, vecb, and vecc be three non- coplanar vectors and vecd be a non -zero , which is perpendicular to (veca + vecb + vecc). Now vecd = (veca xx vecb) sin x + (vecb xx vecc) cos y + 2 (vecc xx veca) . Then

Let veca,vecb and vecc be three vectors such that |veca |=sqrt(3),|vec b|=5 , vec b .vec c = 10 and the angle between vec b and vec c is pi/3, if vec a is perpendicular to the vector vec b xx vec c, then | veca xx (vecbxxvecc)| is equal to __________.

veca=2hati+hatj+2hatk, vecb=hati-hatj+hatk and non zero vector vecc are such that (veca xx vecb) xx vecc = veca xx (vecb xx vecc) . Then vector vecc may be given as

Given vec(a) is perpendicular to vecb+vecc , vecb is perpendicular to vecc+veca and vecc is perpendicular to veca+vecb . If |veca|=1, |vecb|=2, |vecc|=3 , find |veca+vecb+vecc|

If veca + 2 vecb + 3 vecc = vec0 " then " veca xx vecb + vecb xx vecc + vecc xx veca=

Let veca, vecb and vecc are three unit vectors in a plane such that they are equally inclined to each other, then the value of (veca xx vecb).(vecb xx vecc) + (vecb xx vecc). (vecc xx veca)+(vecc xx veca). (veca xx vecb) can be

If vectors, vecb, vecc and vecd are not coplanar, the prove that vector (veca xx vecb) xx (vecc xx vecd) + ( veca xx vecc) xx (vecd xx vecb) + (veca xx vecd) xx (vecb xx vecc) is parallel to veca .

CENGAGE ENGLISH-DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS -Exercises MCQ
  1. Let veca.vecb=0 where veca and vecb are unit vectors and the vector ve...

    Text Solution

    |

  2. veca and vecb are two given vectors. On these vectors as adjacent side...

    Text Solution

    |

  3. If veca xx (vec b xx vecc) is perpendicular to (veca xx vecb ) xx vecc...

    Text Solution

    |

  4. If vecp=(vecbxxvecc)/([(veca,vecb,vecc)]),vecq=(veccxxveca)/([(veca,ve...

    Text Solution

    |

  5. a(1), a(2),a(3) in R - {0} and a(1)+ a(2)cos2x+ a(3)sin^(2)x=0 " for ...

    Text Solution

    |

  6. If veca and vecb are two vectors and angle between them is theta , the...

    Text Solution

    |

  7. Let veca and vecb be two non- zero perpendicular vectors. A vector vec...

    Text Solution

    |

  8. If vector vec b=(t a nalpha,-1,2sqrt(sinalpha//2))a n d vec c=(t a na...

    Text Solution

    |

  9. Let vecr be a unit vector satisfying vecr xx veca = vecb, " where " |v...

    Text Solution

    |

  10. If veca and vecb are unequal unit vectors such that (veca - vecb) xx[ ...

    Text Solution

    |

  11. If veca and vecb are two unit vectors perpenicualar to each other and ...

    Text Solution

    |

  12. If vectors veca and vecb are non collinear then veca/(|veca|)+vecb/(|v...

    Text Solution

    |

  13. If veca and vecb are non - zero vectors such that |veca + vecb| = |vec...

    Text Solution

    |

  14. Let veca vecb and vecc be non- zero vectors aned vecV(1) =veca xx (vec...

    Text Solution

    |

  15. Vectors vecA and vecB satisfying the vector equation vecA+ vecB = vec...

    Text Solution

    |

  16. A vector vecd is equally inclined to three vectors veca=hati-hatj+hatk...

    Text Solution

    |

  17. Vectors perpendicular tohati-hatj-hatk and in the plane of hati+hatj+h...

    Text Solution

    |

  18. If the sides vec(AB) of an equilateral triangle ABC lying in the xy-pl...

    Text Solution

    |

  19. Let hata be a unit vector and hatb a non zero vector non parallel to v...

    Text Solution

    |

  20. veca ,vecb and vecc are unimodular and coplanar. A unit vector vecd is...

    Text Solution

    |