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Let overset(to)(a) =a(1) hat(i) + a(2)...

Let ` overset(to)(a) =a_(1) hat(i) + a_(2) hat(j) + a_(3) hat(k) , overset(to)(b) = b_(1) hat(i) +b_(2) hat(j) +b_(3) hat(k) " and " overset(to)(c) = c_(1) hat(i) +c_(2) hat(j) + c_(3) hat(k)` be three non- zero vectors such that `overset(to)(c )` is a unit vectors perpendicular to both the vectors `overset(to)(a )` and `overset(to)(b)`. If the angle between `overset(to)(a) " and " overset(to)(b)` is `(pi)/(6)` then
`|{:(a_(1),,a_(2),,a_(3)),(b_(1),,b_(2),,b_(3)),(c_(1),,c_(2),,c_(3)):}|^2` is equal to

A

(a) 0

B

(b) 1

C

(c) `1/4(a_(1)^(2)+a_(2)^(2)+a_(2)^(2))(b_(1)^(2) +b_(2)^(2)+b_(2)^(2))`

D

(d)`3/4(a_(1)^(2)+a_(2)^(2)+a_(2)^(2))(b_(1)^(2) +b_(2)^(2)+b_(2)^(2)) (c_(1)^(2) + c_(2)^(2)+c_(2)^(2))`

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The correct Answer is:
To solve the problem, we need to find the square of the scalar triple product of the vectors \( \overset{\to}{a} \), \( \overset{\to}{b} \), and \( \overset{\to}{c} \). Here are the steps to arrive at the solution: ### Step 1: Understand the given vectors We have three vectors: \[ \overset{\to}{a} = a_1 \hat{i} + a_2 \hat{j} + a_3 \hat{k} \] \[ \overset{\to}{b} = b_1 \hat{i} + b_2 \hat{j} + b_3 \hat{k} \] \[ \overset{\to}{c} = c_1 \hat{i} + c_2 \hat{j} + c_3 \hat{k} \] where \( \overset{\to}{c} \) is a unit vector perpendicular to both \( \overset{\to}{a} \) and \( \overset{\to}{b} \). ### Step 2: Use the property of the scalar triple product The scalar triple product can be expressed as: \[ |(\overset{\to}{a}, \overset{\to}{b}, \overset{\to}{c})| = \overset{\to}{a} \cdot (\overset{\to}{b} \times \overset{\to}{c}) \] This can also be written as: \[ |(\overset{\to}{a}, \overset{\to}{b}, \overset{\to}{c})|^2 = |\overset{\to}{a}|^2 |\overset{\to}{b}|^2 |\overset{\to}{c}|^2 \sin^2 \theta \] where \( \theta \) is the angle between vectors \( \overset{\to}{a} \) and \( \overset{\to}{b} \). ### Step 3: Calculate the sine of the angle Given that the angle \( \theta \) between \( \overset{\to}{a} \) and \( \overset{\to}{b} \) is \( \frac{\pi}{6} \): \[ \sin \theta = \sin \left(\frac{\pi}{6}\right) = \frac{1}{2} \] ### Step 4: Substitute the values into the formula Since \( \overset{\to}{c} \) is a unit vector, we have: \[ |\overset{\to}{c}| = 1 \implies |\overset{\to}{c}|^2 = 1 \] Thus, the expression simplifies to: \[ |(\overset{\to}{a}, \overset{\to}{b}, \overset{\to}{c})|^2 = |\overset{\to}{a}|^2 |\overset{\to}{b}|^2 \sin^2 \left(\frac{\pi}{6}\right) \] \[ = |\overset{\to}{a}|^2 |\overset{\to}{b}|^2 \left(\frac{1}{2}\right)^2 = |\overset{\to}{a}|^2 |\overset{\to}{b}|^2 \cdot \frac{1}{4} \] ### Step 5: Express the magnitudes of vectors Let: \[ |\overset{\to}{a}|^2 = a_1^2 + a_2^2 + a_3^2 \] \[ |\overset{\to}{b}|^2 = b_1^2 + b_2^2 + b_3^2 \] Then: \[ |(\overset{\to}{a}, \overset{\to}{b}, \overset{\to}{c})|^2 = \frac{1}{4} (a_1^2 + a_2^2 + a_3^2)(b_1^2 + b_2^2 + b_3^2) \] ### Conclusion Thus, the final result for \( |(\overset{\to}{a}, \overset{\to}{b}, \overset{\to}{c})|^2 \) is: \[ |(\overset{\to}{a}, \overset{\to}{b}, \overset{\to}{c})|^2 = \frac{1}{4} \cdot |(a_1, a_2, a_3), (b_1, b_2, b_3)|^2 \]

To solve the problem, we need to find the square of the scalar triple product of the vectors \( \overset{\to}{a} \), \( \overset{\to}{b} \), and \( \overset{\to}{c} \). Here are the steps to arrive at the solution: ### Step 1: Understand the given vectors We have three vectors: \[ \overset{\to}{a} = a_1 \hat{i} + a_2 \hat{j} + a_3 \hat{k} \] \[ ...
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Let vec a = a_1 hat i + a_2 hat j+ a_3 hat k;vec b = b_1 hat i+ b_2 hat j+ b_3 hat k ; vec c= c_1hat i + c_2 hat j+ c_3 hat k be three non-zero vectors such that vec c is a unit vector perpendicular to both vec a & vec b . If the angle between vec a and vec b is pi/6 , then |(a_1,b_1,c_1),(a_2,b_2,c_2),(a_3,b_3,c_3)|^2=

Let vec a=a_1 hat i+a_2 hat j+a_2 hat k , vec b=b_1 hat i+a_2 hat j+b_2 hat k , and vec c=c_1 hat i+c_2 hat j+c_2 hat k , be three non-zero vectors such that vec c is a unit vector perpendicular to both vectors vec a and vec b . If the angle between a and b is pi//6, then |[a_1,a_2,a_3],[b_1,b_2,b_3],[c_1,c_2,c_3]|^2 is equal to

Knowledge Check

  • The angle between the lines overset(to)( r)=(4 hat(i) - hat(j) )+ lambda(2 hat(i) + hat(j) - 3hat(k) ) and overset(to) (r )=( hat(i) -hat(j) + 2 hat(k) ) + mu (hat(i) - 3 hat(j) - 2 hat(k) ) is

    A
    `pi/6`
    B
    `pi/3`
    C
    `pi/4`
    D
    `pi/2`
  • A vector parallel to the line of intersection of the planes overset(to)( r) (3 hat(i) - hat(j) + hat(k) )=5 and overset(to) (r ) (hat(i) +4 hat(j) - 2 hat(k) )=3 is

    A
    `2hat(i) + 7 hat(j) -13 hat(k)`
    B
    `2hat(i) - 7hat(i) + 13 hat(k)`
    C
    `-2hat(i) + 7 hat(j) + 13 hat(k)`
    D
    `2hat(i) + 7 hat(j) + 13 hat(k)`
  • If the planes overset(to)( r) (2 hat(i) - lambda (j) + 3 hat(k) ) = 0 and overset(to)( r) ( lambda (i) + 5 hat(j) - hat(k) )=5 are perpendicular to each other, then the value of lambda is

    A
    `0`
    B
    `-2`
    C
    `-1`
    D
    `2`
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