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in Three-dimensional geometry by (33.1k points)

Let vector r1 = a1i + b1j + c1k

and vector r2 = a2i + b2j + c2k.

Then cos(θ) = ((a1a2 + b1b+ c1c2)/(√(a12 + b12 + c12) √(a22 + b22 + c22)).

The angle between one diagonal of a unit cube and a diagonal of a face is

1 Answer

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Best answer

Answer is (a) cot–1(√2 )

OP = i + j + k

OL = i + j

OP.OL = 1 + 1

Hence, the angle between a diagonal and a diagonal of a face is 

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