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If a and b are two vectors.then the valu...

If a and b are two vectors.then the value of `(a+b)xx(a-b)` is

A

`2(bxxa)`

B

`-2(bxxa)`

C

`bxxa`

D

`axxb`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the value of \((\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b})\). Let's break this down step by step. ### Step 1: Apply the distributive property of the cross product Using the distributive property of the cross product, we can expand the expression: \[ (\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b}) = \mathbf{a} \times \mathbf{a} + \mathbf{a} \times (-\mathbf{b}) + \mathbf{b} \times \mathbf{a} + \mathbf{b} \times (-\mathbf{b}) \] ### Step 2: Simplify the terms Now, let's simplify each term: 1. \(\mathbf{a} \times \mathbf{a} = \mathbf{0}\) (the cross product of any vector with itself is zero) 2. \(\mathbf{a} \times (-\mathbf{b}) = -(\mathbf{a} \times \mathbf{b})\) 3. \(\mathbf{b} \times \mathbf{a} = -(\mathbf{a} \times \mathbf{b})\) (the cross product is anti-commutative) 4. \(\mathbf{b} \times (-\mathbf{b}) = \mathbf{0}\) Putting these together, we have: \[ (\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b}) = \mathbf{0} - (\mathbf{a} \times \mathbf{b}) - (\mathbf{a} \times \mathbf{b}) + \mathbf{0} \] ### Step 3: Combine the results Now, combine the results: \[ = -\mathbf{a} \times \mathbf{b} - \mathbf{a} \times \mathbf{b} = -2(\mathbf{a} \times \mathbf{b}) \] ### Final Result Thus, the value of \((\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b})\) is: \[ \boxed{-2(\mathbf{a} \times \mathbf{b})} \] ---

To solve the problem, we need to find the value of \((\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b})\). Let's break this down step by step. ### Step 1: Apply the distributive property of the cross product Using the distributive property of the cross product, we can expand the expression: \[ (\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b}) = \mathbf{a} \times \mathbf{a} + \mathbf{a} \times (-\mathbf{b}) + \mathbf{b} \times \mathbf{a} + \mathbf{b} \times (-\mathbf{b}) \] ...
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DC PANDEY ENGLISH-VECTORS-Single Correct
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  6. Two vectors A and B are such that A+B = C and A^2 +B^2 = C^2. If theta...

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  7. If |AxxB| = sqrt3 A.B, then the value of |A+B| is

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  8. If the angle between the vectors A and B is theta, the value of the p...

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  9. Given that P 12, Q = 5 and R = 13 also P+Q=R, then the angle between P...

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  10. Given that P+Q+R= 0. Two out of the three vectors are equal in magnitu...

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  12. The value of n so that vectors 2hati+3hatj-2hatk, 5hati+nhatj+hatk and...

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  15. The resultant of two forces, one double the other in magnitude is perp...

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  16. Three vectors satisfy the relation A.B =0 and A.C=0 then A is paralle...

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  17. The sum of two forces at a point is 16N. if their resultant is normal...

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  18. The sum of two vectors A and B is at right angles to their difference....

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  19. Let vec(C )= vec(A)+vec(B) then

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