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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 of finding the value of \((\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b})\), we can use the properties of the cross product. Let's break it down step by step. ### Step 1: Expand the Expression 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 Each Term Now, we simplify each term in the expanded expression: - \(\mathbf{a} \times \mathbf{a} = \mathbf{0}\) (the cross product of any vector with itself is zero) - \(\mathbf{b} \times \mathbf{b} = \mathbf{0}\) (similarly, the cross product of \(\mathbf{b}\) with itself is also zero) Thus, the expression simplifies to: \[ \mathbf{0} - \mathbf{a} \times \mathbf{b} + \mathbf{b} \times \mathbf{a} - \mathbf{0} \] ### Step 3: Use the Anti-Symmetric Property of Cross Product The cross product is anti-symmetric, which means: \[ \mathbf{b} \times \mathbf{a} = -(\mathbf{a} \times \mathbf{b}) \] Substituting this into our expression gives: \[ -\mathbf{a} \times \mathbf{b} - \mathbf{a} \times \mathbf{b} = -2(\mathbf{a} \times \mathbf{b}) \] ### Final Result Thus, the final value of \((\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b})\) is: \[ -2(\mathbf{a} \times \mathbf{b}) \]

To solve the problem of finding the value of \((\mathbf{a} + \mathbf{b}) \times (\mathbf{a} - \mathbf{b})\), we can use the properties of the cross product. Let's break it down step by step. ### Step 1: Expand the Expression 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-VECTORS-Single Correct
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