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If |A|=2 and |B|=4 and angle between the...

If |A|=2 and |B|=4 and angle between then is `60^(@)` then |A-B|

A

`sqrt(13)`

B

`3sqrt(3)`

C

`sqrt(3)`

D

`2sqrt(3)`

Text Solution

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The correct Answer is:
To find the magnitude of the vector \( |A - B| \), we can use the formula derived from the law of cosines. The formula for the magnitude of the difference of two vectors is given by: \[ |A - B| = \sqrt{|A|^2 + |B|^2 - 2 |A| |B| \cos(\theta)} \] Where: - \( |A| \) is the magnitude of vector \( A \) - \( |B| \) is the magnitude of vector \( B \) - \( \theta \) is the angle between vectors \( A \) and \( B \) ### Step-by-step Solution: 1. **Identify the given values:** - \( |A| = 2 \) - \( |B| = 4 \) - \( \theta = 60^\circ \) 2. **Substitute the values into the formula:** \[ |A - B| = \sqrt{2^2 + 4^2 - 2 \cdot 2 \cdot 4 \cdot \cos(60^\circ)} \] 3. **Calculate \( |A|^2 \) and \( |B|^2 \):** - \( |A|^2 = 2^2 = 4 \) - \( |B|^2 = 4^2 = 16 \) 4. **Calculate \( \cos(60^\circ) \):** - \( \cos(60^\circ) = \frac{1}{2} \) 5. **Substitute these values back into the equation:** \[ |A - B| = \sqrt{4 + 16 - 2 \cdot 2 \cdot 4 \cdot \frac{1}{2}} \] 6. **Simplify the expression:** \[ |A - B| = \sqrt{4 + 16 - 2 \cdot 2 \cdot 4 \cdot \frac{1}{2}} = \sqrt{4 + 16 - 8} \] \[ |A - B| = \sqrt{12} \] 7. **Further simplify \( \sqrt{12} \):** \[ \sqrt{12} = \sqrt{4 \cdot 3} = 2\sqrt{3} \] 8. **Final answer:** \[ |A - B| = 2\sqrt{3} \] ### Conclusion: The magnitude of the vector \( |A - B| \) is \( 2\sqrt{3} \).

To find the magnitude of the vector \( |A - B| \), we can use the formula derived from the law of cosines. The formula for the magnitude of the difference of two vectors is given by: \[ |A - B| = \sqrt{|A|^2 + |B|^2 - 2 |A| |B| \cos(\theta)} \] Where: - \( |A| \) is the magnitude of vector \( A \) ...
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