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KVPY2014MathematicsVector Algebra

What is the angle subtended by an edge of a regular tetrahedron at its center?

Options

  1. A⁻¹ ( -1 2 )
  2. B⁻¹ ( -1 2 )
  3. C⁻¹ ( -1 3 )
  4. D⁻¹ ( -1 3 )

Correct answer

C. ⁻¹ ( -1 3 )

Step-by-step solution

Let side length =2 a array l GA = GB = a 3 2 =- 1 3 array

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