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If veca, vecb and vecc are three non-cop...

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

A

0

B

`[veca vecb vecc]`

C

`2[veca vecb vecc]`

D

`-[veca vecb vecc]`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the expression \((\vec{a} + \vec{b} + \vec{c}) \cdot ((\vec{a} + \vec{b}) \times (\vec{a} + \vec{c}))\). ### Step-by-Step Solution: 1. **Expand the Cross Product**: We first need to compute the cross product \((\vec{a} + \vec{b}) \times (\vec{a} + \vec{c})\). \[ (\vec{a} + \vec{b}) \times (\vec{a} + \vec{c}) = \vec{a} \times \vec{a} + \vec{a} \times \vec{c} + \vec{b} \times \vec{a} + \vec{b} \times \vec{c} \] Since \(\vec{a} \times \vec{a} = \vec{0}\), we can simplify this to: \[ \vec{a} \times \vec{c} + \vec{b} \times \vec{a} + \vec{b} \times \vec{c} \] 2. **Substitute Back into the Dot Product**: Now, substitute this result back into the original expression: \[ (\vec{a} + \vec{b} + \vec{c}) \cdot (\vec{a} \times \vec{c} + \vec{b} \times \vec{a} + \vec{b} \times \vec{c}) \] 3. **Distribute the Dot Product**: We can distribute the dot product: \[ (\vec{a} + \vec{b} + \vec{c}) \cdot (\vec{a} \times \vec{c}) + (\vec{a} + \vec{b} + \vec{c}) \cdot (\vec{b} \times \vec{a}) + (\vec{a} + \vec{b} + \vec{c}) \cdot (\vec{b} \times \vec{c}) \] 4. **Evaluate Each Term**: - The first term: \[ (\vec{a} + \vec{b} + \vec{c}) \cdot (\vec{a} \times \vec{c}) = \vec{a} \cdot (\vec{a} \times \vec{c}) + \vec{b} \cdot (\vec{a} \times \vec{c}) + \vec{c} \cdot (\vec{a} \times \vec{c}) = 0 + \vec{b} \cdot (\vec{a} \times \vec{c}) + 0 = \vec{b} \cdot (\vec{a} \times \vec{c}) \] - The second term: \[ (\vec{a} + \vec{b} + \vec{c}) \cdot (\vec{b} \times \vec{a}) = \vec{a} \cdot (\vec{b} \times \vec{a}) + \vec{b} \cdot (\vec{b} \times \vec{a}) + \vec{c} \cdot (\vec{b} \times \vec{a}) = 0 + 0 + \vec{c} \cdot (\vec{b} \times \vec{a}) = \vec{c} \cdot (\vec{b} \times \vec{a}) \] - The third term: \[ (\vec{a} + \vec{b} + \vec{c}) \cdot (\vec{b} \times \vec{c}) = \vec{a} \cdot (\vec{b} \times \vec{c}) + \vec{b} \cdot (\vec{b} \times \vec{c}) + \vec{c} \cdot (\vec{b} \times \vec{c}) = \vec{a} \cdot (\vec{b} \times \vec{c}) + 0 + 0 = \vec{a} \cdot (\vec{b} \times \vec{c}) \] 5. **Combine the Results**: Now, combine all the results: \[ \vec{b} \cdot (\vec{a} \times \vec{c}) + \vec{c} \cdot (\vec{b} \times \vec{a}) + \vec{a} \cdot (\vec{b} \times \vec{c}) \] This expression is known as the scalar triple product, which can be represented as: \[ \text{Scalar Triple Product} = \vec{a} \cdot (\vec{b} \times \vec{c}) \] 6. **Final Result**: Therefore, the final result is: \[ = \text{Scalar Triple Product} - \text{Scalar Triple Product} = -2 \cdot \text{Scalar Triple Product} \] ### Conclusion: The final answer is: \[ -2 \cdot (\vec{a} \cdot (\vec{b} \times \vec{c})) \]

To solve the problem, we need to evaluate the expression \((\vec{a} + \vec{b} + \vec{c}) \cdot ((\vec{a} + \vec{b}) \times (\vec{a} + \vec{c}))\). ### Step-by-Step Solution: 1. **Expand the Cross Product**: We first need to compute the cross product \((\vec{a} + \vec{b}) \times (\vec{a} + \vec{c})\). \[ (\vec{a} + \vec{b}) \times (\vec{a} + \vec{c}) = \vec{a} \times \vec{a} + \vec{a} \times \vec{c} + \vec{b} \times \vec{a} + \vec{b} \times \vec{c} ...
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CENGAGE ENGLISH-DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS -single correct answer type
  1. If veca,vecb and vecc are non coplanar and unit vectors such that veca...

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  2. Let vecu,vecv and vecw be vectors such that vecu+ vecv + vecw =0 if |v...

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  3. If veca, vecb and vecc are three non-coplanar vectors, then (veca + ve...

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  4. Let vecp,vecq, vecr be three mutually perpendicular vectors of the sam...

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

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  6. Let veca = 2i + j+k, vecb = i+ 2j -k and a unit vector vecc be coplana...

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  7. If the vectors veca,vecb,vecc form the sides BC,CA and AB respectively...

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  8. Let the vectors veca, vecb,vecc and vecd be such that (vecaxxvecb)xx(v...

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  9. If veca,vecb, vecc are unit coplanar vectors then the scalar triple pr...

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  10. if hata, hatb and hatc are unit vectors. Then |hata - hatb|^(2) + |hat...

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  11. If veca and vecb are two unit vectors such that veca+2vecb and 5veca-4...

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  12. Let vecV = 2hati +hatj - hatk and vecW= hati + 3hatk . if vecU is a u...

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  13. Find the value of a so that the volume of the parallelopiped formed b...

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

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  15. The unit vector which is orthogonal to the vector 5hati + 2hatj + 6hat...

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  16. if veca , vecb and vecc are three non-zero, non- coplanar vectors and ...

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  17. Let veca=hati+2hatj +hatk, vec=hati-hatj+hatk and vecc=hati+hatj-hatk....

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  18. Lelt two non collinear unit vectors hata and hatb form and acute angle...

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  19. If veca,vecb,vecc and vecd are unit vectors such that (vecaxxvecb).(ve...

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  20. Two adjacent sides of a parallelogram A B C D are given by vec A B=...

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