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Let alpha, beta and gamma be distinct re...

Let `alpha, beta and gamma` be distinct real numbers. The points with position vectors `alpha hat(i) + beta hat(j) + gamma hat(k), beta hat(i) + gamma hat(j) + alpha hat(k) and gamma hat(i) + alpha hat(j) + beta hat(k)`

A

A. Are collinear

B

B. Form an equilateral triangle

C

C. Form a scalene triangle

D

D. Form a right-angled triangle

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The correct Answer is:
To determine the relationship between the points with the given position vectors, we will follow these steps: ### Step 1: Define the Position Vectors Let: - \( A = \alpha \hat{i} + \beta \hat{j} + \gamma \hat{k} \) - \( B = \beta \hat{i} + \gamma \hat{j} + \alpha \hat{k} \) - \( C = \gamma \hat{i} + \alpha \hat{j} + \beta \hat{k} \) ### Step 2: Find the Vector \( \overrightarrow{AB} \) The vector \( \overrightarrow{AB} \) can be computed as: \[ \overrightarrow{AB} = B - A = (\beta - \alpha) \hat{i} + (\gamma - \beta) \hat{j} + (\alpha - \gamma) \hat{k} \] ### Step 3: Calculate the Magnitude of \( \overrightarrow{AB} \) The magnitude of \( \overrightarrow{AB} \) is given by: \[ |\overrightarrow{AB}| = \sqrt{(\beta - \alpha)^2 + (\gamma - \beta)^2 + (\alpha - \gamma)^2} \] ### Step 4: Find the Vector \( \overrightarrow{BC} \) Now, compute the vector \( \overrightarrow{BC} \): \[ \overrightarrow{BC} = C - B = (\gamma - \beta) \hat{i} + (\alpha - \gamma) \hat{j} + (\beta - \alpha) \hat{k} \] ### Step 5: Calculate the Magnitude of \( \overrightarrow{BC} \) The magnitude of \( \overrightarrow{BC} \) is: \[ |\overrightarrow{BC}| = \sqrt{(\gamma - \beta)^2 + (\alpha - \gamma)^2 + (\beta - \alpha)^2} \] ### Step 6: Find the Vector \( \overrightarrow{CA} \) Next, compute the vector \( \overrightarrow{CA} \): \[ \overrightarrow{CA} = A - C = (\alpha - \gamma) \hat{i} + (\beta - \alpha) \hat{j} + (\gamma - \beta) \hat{k} \] ### Step 7: Calculate the Magnitude of \( \overrightarrow{CA} \) The magnitude of \( \overrightarrow{CA} \) is: \[ |\overrightarrow{CA}| = \sqrt{(\alpha - \gamma)^2 + (\beta - \alpha)^2 + (\gamma - \beta)^2} \] ### Step 8: Compare the Magnitudes Now we compare the magnitudes: - \( |\overrightarrow{AB}| = |\overrightarrow{BC}| = |\overrightarrow{CA}| \) Since all three sides are equal, we conclude that the points \( A, B, C \) form an equilateral triangle. ### Final Answer Thus, the points with the given position vectors form an equilateral triangle. ---
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