Find the angle between the diagonals of a cube with edges of length "a".

Options

A. `sin^(-1)(1//3)`
B. `cos^(-1)(1//3)`
C. `tan^(-1)(1//3)`
D. `cot^(-1)(1//3)`

Answer

B

Explanation

`vecd(1)=hati+hatj+hatk, vecd_(2)=hati+hatj-hatk, cos theta=(vecd_(1)vecd_(2))/(d_(1)d_(2))`