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Let hata be a unit vector and hatb a non...

Let `hata` be a unit vector and `hatb` a non zero vector non parallel to `veca`. Find the angles of the triangle tow sides of which are represented by the vectors. `sqrt(3)(hatxxvecb)and vecb-(hata.vecb)hata`

A

`tan ^(-1)(sqrt3)`

B

`tan ^(-1)(1//sqrt3)`

C

`cot^(-1)(0)`

D

tant^(-1)(1)`

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To solve the problem, we need to find the angles of a triangle whose two sides are represented by the vectors \( \sqrt{3} \hat{b} \) and \( \hat{b} - (\hat{a} \cdot \hat{b}) \hat{a} \). ### Step 1: Identify the vectors Let: - \( \vec{v_1} = \sqrt{3} \hat{b} \) - \( \vec{v_2} = \hat{b} - (\hat{a} \cdot \hat{b}) \hat{a} \) ### Step 2: Check for orthogonality To find the angle between the two vectors, we first check if they are orthogonal. If \( \vec{v_1} \cdot \vec{v_2} = 0 \), then the angle between them is \( 90^\circ \). Calculating the dot product: \[ \vec{v_1} \cdot \vec{v_2} = \sqrt{3} \hat{b} \cdot \left(\hat{b} - (\hat{a} \cdot \hat{b}) \hat{a}\right) \] \[ = \sqrt{3} (\hat{b} \cdot \hat{b}) - \sqrt{3} (\hat{b} \cdot \hat{a})(\hat{a} \cdot \hat{b}) \] Since \( \hat{b} \cdot \hat{b} = 1 \) (because \( \hat{b} \) is a unit vector), we have: \[ = \sqrt{3} - \sqrt{3} (\hat{b} \cdot \hat{a})^2 \] Setting this equal to zero gives: \[ \sqrt{3} - \sqrt{3} (\hat{b} \cdot \hat{a})^2 = 0 \] \[ \Rightarrow 1 - (\hat{b} \cdot \hat{a})^2 = 0 \] \[ \Rightarrow (\hat{b} \cdot \hat{a})^2 = 1 \] This implies \( \hat{b} \cdot \hat{a} = 1 \) or \( \hat{b} \cdot \hat{a} = -1 \). Since \( \hat{b} \) is not parallel to \( \hat{a} \), we can conclude that they are orthogonal. ### Step 3: Use the sine law Using the sine law in triangle, we can express the relationship between the sides and angles: \[ \frac{\vec{v_2}}{\sin(\theta)} = \frac{\vec{v_1}}{\sin(90^\circ)} \] This simplifies to: \[ \frac{\hat{b} - (\hat{a} \cdot \hat{b}) \hat{a}}{\sin(\theta)} = \frac{\sqrt{3} \hat{b}}{1} \] From this, we can derive: \[ \sin(\theta) = \frac{\hat{b} - (\hat{a} \cdot \hat{b}) \hat{a}}{\sqrt{3} \hat{b}} \] ### Step 4: Calculate the angle Using the relationship \( \tan(\theta) = \frac{\sin(\theta)}{\cos(\theta)} \), we can find \( \theta \): \[ \tan(\theta) = \frac{1}{\sqrt{3}} \Rightarrow \theta = \frac{\pi}{6} \] ### Conclusion The angles of the triangle formed by the two sides represented by the vectors \( \sqrt{3} \hat{b} \) and \( \hat{b} - (\hat{a} \cdot \hat{b}) \hat{a} \) is \( \frac{\pi}{6} \) radians or \( 30^\circ \).

To solve the problem, we need to find the angles of a triangle whose two sides are represented by the vectors \( \sqrt{3} \hat{b} \) and \( \hat{b} - (\hat{a} \cdot \hat{b}) \hat{a} \). ### Step 1: Identify the vectors Let: - \( \vec{v_1} = \sqrt{3} \hat{b} \) - \( \vec{v_2} = \hat{b} - (\hat{a} \cdot \hat{b}) \hat{a} \) ### Step 2: Check for orthogonality ...
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CENGAGE ENGLISH-DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS -Exercises MCQ
  1. Vectors perpendicular tohati-hatj-hatk and in the plane of hati+hatj+h...

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  2. If the sides vec(AB) of an equilateral triangle ABC lying in the xy-pl...

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  3. Let hata be a unit vector and hatb a non zero vector non parallel to v...

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  4. veca ,vecb and vecc are unimodular and coplanar. A unit vector vecd is...

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  5. If veca + 2 vecb + 3 vecc = vec0 " then " veca xx vecb + vecb xx vecc...

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  6. Let veca and vecb be two non-collinear unit vectors. If vecu=veca-(vec...

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  7. if veca xx vecb = vecc ,vecb xx vecc = veca , " where " vecc ne vec0 ...

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  8. Let veca, vecb, and vecc be three non- coplanar vectors and vecd be a ...

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  9. If vec a , vec b , a n d harr c are three unit vecrtors such that ...

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  10. If in triangle ABC, vec(AB) = vecu/|vecu|-vecv/|vecv| and vec(AC) = (...

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  11. [vecaxx vecb " " vecc xx vecd " " vecexx vecf] is equal to

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  12. The scalars l and m such that lveca + m vecb =vecc, " where " veca, ve...

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  13. If (veca xx vecb) xx (vecc xx vecd) . (veca xx vecd) =0 then which of ...

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  14. A ,B ,Ca n dD are four points such that vec A B=m(2 hat i-6 hat j+2 h...

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  15. If the vectors veca, vecb, vecc are non -coplanar and l,m,n are distin...

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  16. Let vec(alpha)=ahati+bhatj+chatk, vec(beta)=bhati+chatj+ahatk and vec(...

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  17. if vectors vecA = 2hati + 3hatj + 4hatk , vecB = hati + hatj + 5hatk a...

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  18. If veca=xhati + y hatj + zhatk, vecb= yhati + zhatj + xhatk and vecc=...

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  19. If veca xx (vecbxx vecc)= (veca xx vecb)xxvecc then

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  20. A vector vecd is equally inclined to three vectors veca=hati-hatj+hatk...

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